[3006.x] Ensure sync from _grains occurs before attempting pillar compilation in case custom grain used in pillar file

[dmurphy18]

What does this PR do?

Ensures that grains are sync'd before loading grains and then compiling pillar, since there could be custom grains used in pillar files, which will throw rendering errors if not found.

What issues does this PR fix or reference?

Fixes:#65027

Previous Behavior

Would throw rendering errors if custom grains in salt://_grains were used in pillar files.

New Behavior

No rendering errors thrown if custom grains in salt://_grains were used in pillar files, and custom grains values available in pillar

Test still to be written

A very old PR #13011(d83e663), A change was made to not refresh on sync_all. I believe this was in error, the previous code did refresh, and the changes was made to save a module load, but what about everything else, like grains. Also the old code would not refresh if local so as to not fire events, and I am not sure that that reasoning holds almost 10 years later, either.
Welcome close examination and reasoning of that change in salt/state.py.

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

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