* Auth integration with AppCheck (#10798)
* Auth App check integration without unit testing
* Add Unitest for AppCheck Auth Integration
* Style the format for Auth-Appcheck Integration
* Fix typo in import for FIRAppCheckInterop
* Style this file
* Fix wrong import
* Fix style for this file
* Fix style in this file
* Add Source path for FIRAppCheckInterop
* Add self to async block in Unit Test
* Fix: pass appcheckInterop to request configuration
* style the fixed files
* revert files that are only for local testing
* modify init method to avoid more changes
* remove extra comments
* upload for debug unit test
* Revert Sample changes and add appcheck into unit tests
* Fix issues in FIRAuthRequestConfiguration and typos in unit tests
* fix error loading and revert pod files
* Add spaces to keep style consistent
* pass appCheckToken as URL fragment (#10877)
* pass appCheckToken as URL fragment
* pass appcheck token as url fragments to phone provider
* for test purpose only: commented async function
* test if it is google cloud error
* formatting the file
* formatting the file
* fix comments issues
* remove printing function
* remove unused property
* Adding Unit test for passing appchecktoekn as a url fragment
* add import for FIRAppCheckTokenResultInterop
* Add separate file for FIRFakeAppCheck and Modify accordingly
* add copyright comments for bewly created files
* Add declaration for completion in FIRFakeAppCheck
* add correct param decalaration
* clean FIRFakeAppCheck.h
* add method in FIRAppcheck.h to avoid complaints
* correct copyright info
* fix typo in FIRFakeAppCheck.m
* Recover declarations
* solve comments issues
* Add changes to unit tests for changes in FIRAuthRequestConfiguration
* Add changelog
* Edit changelog
