Remove depreciation warning when use default remote tasks logging handlers

[Taragolis]

All of the default remote task handlers which inherited from FileTaskHandler pass value from [logging] log_filename_template value to class args filename_template.

• airflow.providers.amazon.aws.log.s3_task_handler.S3TaskHandler
• airflow.providers.amazon.aws.log.cloudwatch_task_handler.CloudwatchTaskHandler
• airflow.providers.google.cloud.log.gcs_task_handler.GCSTaskHandler
• airflow.providers.microsoft.azure.log.wasb_task_handler.WasbTaskHandler
• airflow.providers.alibaba.cloud.log.oss_task_handler.OSSTaskHandler
• airflow.providers.elasticsearch.log.es_task_handler.ElasticsearchTaskHandler

As result when enabled remote logging (e.g. S3 Logging) quite a few deprecation warnings appear in airflow services logs

/home/airflow/.local/lib/python3.9/site-packages/airflow/utils/log/file_task_handler.py:52 DeprecationWarning: Passing filename_template to FileTaskHandler is deprecated and has no effect

This handlers do not use internally filename_template attribute ( check for main and first version of each handlers), so it should be safe set None for all of them.

closes: #25743
related: #24153

cc: @uranusjr

[Taragolis]

I can't find any usage of this variable outside of airflow/config_templates/airflow_local_settings.py

[uranusjr]

It shouldn’t be used anywhere else (should just read from conf). This can be removed.

[uranusjr]

I think we can remove FILENAME_TEMPLATE outright, but this is OK as well.