Update FakeCredentials

Author: DylanRussell

instrumentation-genai/opentelemetry-instrumentation-google-genai/tests/common/auth.py

@@ -16,5 +16,8 @@
 
 
 class FakeCredentials(google.auth.credentials.AnonymousCredentials):
+    def __init__(self):
+        self.token = 'a'
+        self._quota_project_id = 'a'
     def refresh(self, request):
         pass