ref(alerts): Remove INC-666 feature flag

[ceorourke]

The new processor is out! No more flag! Options automator PR: https://github.com/getsentry/sentry-options-automator/pull/2084

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 78.24%. Comparing base (819be93) to head (77111f9). Report is 22 commits behind head on master.

Files	Patch %	Lines
src/sentry/rules/processing/processor.py	33.33%	1 Missing and 1 partial :warning:

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #75798   +/-   ##
=======================================
  Coverage   78.24%   78.24%           
=======================================
  Files        6817     6816    -1     
  Lines      303640   303671   +31     
  Branches    52226    52234    +8     
=======================================
+ Hits       237571   237599   +28     
- Misses      59685    59686    +1     
- Partials     6384     6386    +2     

Files	Coverage Δ
src/sentry/api/endpoints/project_rules.py	95.59% <100.00%> (-0.02%)	:arrow_down:
src/sentry/features/temporary.py	100.00% <ø> (ø)
src/sentry/rules/processing/processor.py	77.98% <33.33%> (+0.15%)	:arrow_up:

... and 23 files with indirect coverage changes