[core][logging][ipython] Fix log buffering when consecutive runs within ray log dedup window

[rickyyx]

Why are these changes needed?

Related issue number

Fixes #34831

The issue is when tasks runs within the same job are executed and producing logs, log lines will be dedup for better observability.

So ray might be buffering some lines, in case there are logs that could be dedup within the same RAY_DEDUP_LOGS_AGG_WINDOW_S. This will show up as logs line not available until future ray tasks runs since buffer is not flushed when there's no activity (no job done, no new task)

This PR adds callbacks to the post_execute to flush the log lines in log monitor when execution in shell took place.

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    method in Tune, I've added it in doc/source/tune/api/ under the
    corresponding .rst file.
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• Testing Strategy
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