Enhance FirebaseAuthCode quality (#13751)

Author: MojtabaHs

FirebaseAuth/Tests/SampleSwift/ObjCApiTests/FIRAuthApiTestsBase.m

@@ -46,7 +46,7 @@ - (void)signInAnonymously {
                                handler:^(NSError *error) {
                                  if (error != nil) {
                                    XCTFail(@"Failed to wait for expectations "
-                                           @"in anonymousy sign in. Error: %@",
+                                           @"in anonymously sign in. Error: %@",
                                            error.localizedDescription);
                                  }
                                }];

FirebaseAuth/Tests/Unit/GetProjectConfigTests.swift

@@ -48,7 +48,7 @@ class GetProjectConfigTests: RPCBaseTests {
     )
   }
 
-  /** @fn testSuccessFulGetProjectConfigRequest
+  /** @fn testSuccessfulGetProjectConfigRequest
       @brief This test checks for a successful response
    */
   func testSuccessfulGetProjectConfigRequest() async throws {

FirebaseAuth/Tests/Unit/RPCBaseTests.swift

@@ -105,7 +105,7 @@ class RPCBaseTests: XCTestCase {
   }
 
   /** @fn checkBackendError
-      @brief This test checks error messagess from the backend map to the expected error codes
+      @brief This test checks error messages from the backend map to the expected error codes
    */
   func checkBackendError(request: any AuthRPCRequest,
                          message: String = "",