Validate the precision input earlier

[carmocca]

What does this PR do?

See title. This ensures that self.precision is one of the allowed values even when set_precision_plugin hasn't been called yet.

Part of #9287

Does your PR introduce any breaking changes? If yes, please list them.

None

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[tchaton]

LGMT !

[codecov]

Codecov Report

Merging #9763 (fdc7a05) into master (6429de8) will increase coverage by 4%.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master   #9763    +/-   ##
=======================================
+ Coverage      89%     93%    +4%     
=======================================
  Files         179     179            
  Lines       15831   15833     +2     
=======================================
+ Hits        14053   14676   +623     
+ Misses       1778    1157   -621