Improve fetching logs from AWS

[vincbeck]

Fetching logs from AWS CloudWatch can take a lot of times or even fail when the log stream is old and no time boundary is specified when querying CloudWatch.

Example: if you try to look at the logs of an old task on the Airflow UI, it can be very slow or even fail doing so.

By setting start_time and end_time (end_time is the most important), it improves drastically the latency. CloudWatch team recommended adding end time for performance to restrict the search space. I tested it with a 10 days old task and I could experience an improvement from 5 seconds to 1 second when fetching task logs from the UI.

Resolves #32897

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[o-nikolas]

Changes look good! But maybe some unit tests for the changes to get_cloudwatch_logs and maybe get_log_events?

[vincbeck]

Changes look good! But maybe some unit tests for the changes to get_cloudwatch_logs and maybe get_log_events?

Good call! I added some unit tests for get_cloudwatch_logs. I dont think it is worth adding unit tests for get_log_events