chore: Deprecates the KV_STORE feature flag

[michael-s-molina]

SUMMARY

As part of the 4.0 approved initiatives, this PR deprecates the KV_STORE feature flag and its related assets such as the API endpoint and keyvalue table. The main dependency of this feature is the SHARE_QUERIES_VIA_KV_STORE feature flag which allows sharing SQL Lab queries without the necessity of saving the query. Our intention is to use the permalink feature to implement this use case before 5.0 and that's why we are deprecating the feature flag now.

TESTING INSTRUCTIONS

CI.

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ea4e9a6) 69.16% compared to head (d0f2c4e) 69.16%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #26450   +/-   ##
=======================================
  Coverage   69.16%   69.16%           
=======================================
  Files        1948     1948           
  Lines       76054    76056    +2     
  Branches     8493     8493           
=======================================
+ Hits        52601    52603    +2     
  Misses      21273    21273           
  Partials     2180     2180           

Flag	Coverage Δ
hive	53.68% <100.00%> (+<0.01%)	⬆️
mysql	78.07% <100.00%> (+<0.01%)	⬆️
postgres	78.17% <100.00%> (+<0.01%)	⬆️
presto	53.63% <100.00%> (+<0.01%)	⬆️
python	82.85% <100.00%> (+<0.01%)	⬆️
sqlite	77.76% <100.00%> (+<0.01%)	⬆️
unit	55.86% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.