Do not use deprecated TokenCache.find() (#36714)

azure-identity already requires msal>=1.29.0, so this should be safe.

Fixes #36713

Author: akx

sdk/identity/azure-identity/azure/identity/_internal/managed_identity_client.py

@@ -82,8 +82,10 @@ def _process_response(self, response: PipelineResponse, request_time: int) -> Ac
 
     def get_cached_token(self, *scopes: str) -> Optional[AccessToken]:
         resource = _scopes_to_resource(*scopes)
-        tokens = self._cache.find(TokenCache.CredentialType.ACCESS_TOKEN, target=[resource])
-        for token in tokens:
+        for token in self._cache.search(
+            TokenCache.CredentialType.ACCESS_TOKEN,
+            target=[resource],
+        ):
             expires_on = int(token["expires_on"])
             if expires_on > time.time():
                 return AccessToken(token["secret"], expires_on)