fix: Add service account authentication verification with gcloud(Issue #69)

[doooosoooo]

• Add verify_firebase_auth function for service account authentication check
• Use gcloud auth to get access token before Firebase CLI execution
• Implement retry mechanism with max 30s wait time
• Prevent deployment failures caused by authentication timing issues

[doooosoooo]

Problem

When using service account authentication in the Firebase App Distribution step,
there can be timing issues where the deployment attempts to proceed before the
authentication process is fully completed, leading to deployment failures.

Solution

• Added a verify_firebase_auth function that:
  • Explicitly authenticates with gcloud using the service account
  • Verifies the authentication status using firebase projects:list
  • Implements a retry mechanism (max 30s) to ensure authentication is complete
  • Fails early if authentication cannot be verified

Test Results

• Tested with service account authentication
• Successfully prevented timing-related deployment failures
• Maintains backward compatibility with Firebase token authentication method

The changes only affect service account authentication flow and do not modify
the existing Firebase token authentication behavior.