Replace plugin.log with file_hook.log

What does this MR do?

Change file name from plugin.log to file_hook.log in FileHookLogger. To match feature and class name.

This MR does not include any migration for existing file. I am not sure it is necessary but I am open to suggestions.

For #196846 (closed)

Does this MR meet the acceptance criteria?

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• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
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