🐛 fix(aci): fix slack interactions during rollout

[iamrajjoshi]

resolves SENTRY-48VA

basically because we are rolling out ACI, when we try to build a notification using Rules, we must populate the "legacy_rule_id" field. we weren't doing that so when we went to send a notification, we were erroring out (since we were going down the aci backend rollout path).

this pr fixes it by correctly inserting the legacy_rule_id key, similar to

sentry/src/sentry/notifications/notification_action/types.py

Line 168 in db7de1e

data["actions"][0]["legacy_rule_id"] = alert_rule_workflow.rule_id

also wrote a test to verify this behavior.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #98503      +/-   ##
==========================================
+ Coverage   81.13%   81.18%   +0.04%     
==========================================
  Files        8541     8544       +3     
  Lines      376472   376570      +98     
  Branches    23952    23952              
==========================================
+ Hits       305441   305703     +262     
+ Misses      70666    70502     -164     
  Partials      365      365              

[Christinarlong]

rtust u bro