Allow influxdb-client to be completely tested by stubtest (#9529)

stubs/influxdb-client/@tests/stubtest_allowlist.txt

@@ -7,7 +7,3 @@ influxdb_client.client.write_api_async.DEFAULT_WRITE_PRECISION
 
 # Metaclass problem inherited from urllib3.
 influxdb_client.client.write.retry.WritesRetry
-
-# Requires numpy and pandas to be installed.
-influxdb_client.client.util.date_utils_pandas
-influxdb_client.extras

stubs/influxdb-client/METADATA.toml

@@ -3,3 +3,4 @@ requires = ["types-urllib3"]
 
 [tool.stubtest]
 ignore_missing_stub = false
+extras = ["extra"]