feat(visibility): Add static sampling to organization tag keys

[gggritso]

Related to #61999. For organizations who are getting timeouts while fetching organization tags, use a ClickHouse SAMPLE N instead of a sampling rate.

The intent is to give this a try, and then roll out to everyone if it works out well. I'm going with 1,000,000 as a starting point, I'll be tweaking that number soon when I run some experiments.

[codecov]

Codecov Report

Attention: Patch coverage is 71.42857% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/sentry/tagstore/snuba/backend.py	66.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #80332      +/-   ##
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- Coverage   78.31%   78.31%   -0.01%     
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  Files        7192     7192              
  Lines      318363   318369       +6     
  Branches    43885    43886       +1     
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+ Hits       249337   249339       +2     
- Misses      62670    62671       +1     
- Partials     6356     6359       +3