Default enable projects_preloader_fix feature flag

What does this MR do and why?

Default enable projects_preloader_fix feature flag. This feature flag has been globally enabled.

This FF has successfully reduced slow database performance.

Screenshots or screen recordings

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How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #378858 (closed)