ref(crons): Drop last_state_change from db

[evanpurkhiser]

No longer needed after GH-66353

[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/0664_monitor_drop_last_state_change_db.py ()

--
-- Custom state/database change combination
--

                ALTER TABLE "sentry_monitorenvironment" DROP COLUMN "last_state_change";

[wedamija]

Add it as nullable here. Mostly for dev but this reverse will fail otherwise

[evanpurkhiser]

I think default it is nullable without NOT NULL right?

[evanpurkhiser]

Refrence: https://www.postgresql.org/docs/7.3/sql-altertable.html#:~:text=The%20new%20column%20always%20comes,to%20set%20the%20default%20afterwards.

In the current implementation of ADD COLUMN, default and NOT NULL clauses for the new column are not supported. The new column always comes into being with all values NULL. You can use the SET DEFAULT form of ALTER TABLE to set the default afterwards.

right?

[wedamija]

I always get this backwards, because in Django it's the opposite!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.29%. Comparing base (1ca26bc) to head (fdad04d).
Report is 3 commits behind head on master.

❗ Current head fdad04d differs from pull request most recent head 741f92a. Consider uploading reports for the commit 741f92a to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #66429       +/-   ##
===========================================
+ Coverage   57.49%   84.29%   +26.80%     
===========================================
  Files        5292     5309       +17     
  Lines      236552   237233      +681     
  Branches    40959    41042       +83     
===========================================
+ Hits       135999   199974    +63975     
+ Misses     100329    37040    -63289     
+ Partials      224      219        -5     

see 1933 files with indirect coverage changes

[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/0665_monitor_drop_last_state_change_db.py ()

--
-- Custom state/database change combination
--

                ALTER TABLE "sentry_monitorenvironment" DROP COLUMN "last_state_change";