feat(insights): Query performance scores with hardcoded weights

[edwardgou-sentry]

Updates the performance_score function in discover metrics to allow calculating total performance score with hardcoded weights. This may be useful in scenarios where certain webvitals are missing or low throughput which can cause issues when dynamically weighting vitals.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.00%. Comparing base (fcb48c7) to head (e5873f8).
Report is 23 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #73468   +/-   ##
=======================================
  Coverage   78.00%   78.00%           
=======================================
  Files        6635     6634    -1     
  Lines      296661   296711   +50     
  Branches    51087    51097   +10     
=======================================
+ Hits       231416   231460   +44     
- Misses      58863    58868    +5     
- Partials     6382     6383    +1     

Files	Coverage Δ
src/sentry/search/events/constants.py	100.00% <100.00%> (ø)
src/sentry/search/events/datasets/metrics.py	83.06% <100.00%> (+1.01%)	⬆️

... and 70 files with indirect coverage changes