【Flutter開発】FireBase設定追加時に発生する「error: unable to read input file〜GoogleService-Info.plist」の解決方法に関して

前提・実現したいこと

Flutterにて、FireBaseの設定を追加したところ
以下のエラーメッセージが発生しました。

発生している問題・エラーメッセージ

Launching lib/main.dart on iPhone 12 in debug mode...
Running pod install...
Running Xcode build...
flutter: Ad loaded.
Xcode build done. 28.6s
Failed to build iOS app
Error output from Xcode build:
↳
--- xcodebuild: WARNING: Using the first of multiple matching destinations:
{ platform:iOS Simulator, id:dvtdevice-DVTiOSDeviceSimulatorPlaceholder-iphonesimulator:placeholder, name:Any iOS Simulator Device }
{ platform:iOS Simulator, id:4ED39797-A537-45FA-8CEE-5AC85B4C5746, OS:15.0, name:iPad (9th generation) }
{ platform:iOS Simulator, id:47C7F479-C3E6-4A83-8914-2A53EC2AEDD6, OS:15.0, name:iPad Air (4th generation) }
{ platform:iOS Simulator, id:A456FA9F-2DEA-4B8C-B40C-B32D25353917, OS:15.0, name:iPad Pro (9.7-inch) }
{ platform:iOS Simulator, id:8720CE5B-7B6A-49D3-8438-F95AAE4FCDF2, OS:15.0, name:iPad Pro (11-inch) (3rd generation) }
{ platform:iOS Simulator, id:4D3A273A-408C-4BF5-99EB-F951943229FD, OS:15.0, name:iPad Pro (12.9-inch) (5th generation) }
{ platform:iOS Simulator, id:F01EA809-DA7E-4B17-BCF7-E6768371BD8D, OS:15.0, name:iPad mini (6th generation) }
{ platform:iOS Simulator, id:80909220-0644-4638-B954-E9FCDE369FA2, OS:15.0, name:iPhone 8 }
{ platform:iOS Simulator, id:24B90BD8-C956-409D-B593-AD7381FBE5B2, OS:15.0, name:iPhone 8 Plus }
{ platform:iOS Simulator, id:DF558E80-5142-4C9D-9A56-EACAFCAE75FE, OS:15.0, name:iPhone 11 }
{ platform:iOS Simulator, id:DE838587-7ADD-4D7B-9B62-AB02E1D83EF6, OS:15.0, name:iPhone 11 Pro }
{ platform:iOS Simulator, id:C3D1C79E-6CD6-43AB-B92E-6140036FD8CF, OS:15.0, name:iPhone 11 Pro Max }
{ platform:iOS Simulator, id:BCFE775B-FEFF-4C65-8893-5808F9E3A538, OS:15.0, name:iPhone 12 }
{ platform:iOS Simulator, id:787C1271-2EF6-4648-8655-20E83AB68873, OS:15.0, name:iPhone 12 Pro }
{ platform:iOS Simulator, id:B73EA17D-F600-4274-9DAE-1AA02B6419A2, OS:15.0, name:iPhone 12 Pro Max }
{ platform:iOS Simulator, id:AA0CAA5E-B6A0-4D0C-9EED-68AFA8E98D28, OS:15.0, name:iPhone 12 mini }
{ platform:iOS Simulator, id:30A31473-1D72-4BDB-B657-3FDE0FFFFDFB, OS:15.0, name:iPhone 13 }
{ platform:iOS Simulator, id:D7160F66-8CB4-4F5E-B234-054AAC15BC38, OS:15.0, name:iPhone 13 Pro }
{ platform:iOS Simulator, id:45E4C8F8-2BBA-4E9E-BE7F-618DF4B9F749, OS:15.0, name:iPhone 13 Pro Max }
{ platform:iOS Simulator, id:8639C1A0-00FC-413F-94FA-35E8ABEC3091, OS:15.0, name:iPhone 13 mini }
{ platform:iOS Simulator, id:B6C6656A-C309-405C-AFDB-D6123BF4D17B, OS:15.0, name:iPhone SE (2nd generation) }
{ platform:iOS Simulator, id:82643310-4E92-436A-9A80-1BFEDCABB388, OS:15.0, name:iPod touch (7th generation) }
{ platform:macOS, arch:arm64, variant:Designed for [iPad,iPhone], id:00008103-000A79E90EDB001E }
{ platform:iOS, id:dvtdevice-DVTiPhonePlaceholder-iphoneos:placeholder, name:Any iOS Device }
** BUILD FAILED **

Xcode's output:
↳
error: unable to read input file '/Users/XXXXXXXXX/Downloads/GoogleService-Info.plist': fopen(/Users/XXXXXXXXX/Downloads/GoogleService-Info.plist, rb): Operation not permitted (1) (in target 'Runner' from project 'Runner')
note: Using new build system
note: Planning
note: Build preparation complete
note: Building targets in parallel
/Users/XXXXXXXXX/Desktop/RiYu/futsal_develop/ios/Pods/Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 15.0.99. (in target 'BoringSSL-GRPC' from project 'Pods')
/Users/XXXXXXXXX/Desktop/RiYu/futsal_develop/ios/Pods/Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 15.0.99. (in target 'abseil' from project 'Pods')
/Users/XXXXXXXXX/Desktop/RiYu/futsal_develop/ios/Pods/Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 15.0.99. (in target 'gRPC-Core' from project 'Pods')
/Users/XXXXXXXXX/Desktop/RiYu/futsal_develop/ios/Pods/Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 15.0.99. (in target 'gRPC-C++' from project 'Pods')
/Users/XXXXXXXXX/Desktop/RiYu/futsal_develop/ios/Pods/Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 15.0.99. (in target 'gRPC-C++-gRPCCertificates-Cpp' from project 'Pods')
/Users/XXXXXXXXX/Desktop/RiYu/futsal_develop/ios/Pods/Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 15.0.99. (in target 'Flutter' from project 'Pods')
/Users/XXXXXXXXX/Desktop/RiYu/futsal_develop/ios/Pods/Pods.xcodeproj: warning: The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 15.0.99. (in target 'leveldb-library' from project 'Pods')

Could not build the application for the simulator.
Error launching application on iPhone 12.

試したこと

・「GoogleService-Info.plist」の再ダウンロードしたのち、Xcodeに再配置
・Project>iOS配下にて、「pod install --repo-update」を実行
・「flutter clean」→Project>iOS配下のpodファイルを削除→「Pod install」