ref(dynamic-sampling): Drop CustomDynamicSamplingRule tables

[shellmayr]

Step 2 of the table deletion process: physically drop the sentry_customdynamicsamplingrule and sentry_customdynamicsamplingruleproject tables from PostgreSQL.
The previous migration (1063) already removed foreign key constraints and moved the models to pending deletion state.

Closes TET-1957

[linear-code]

TET-1957 Remove CustomDynamicSamplingRule table

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

Bugbot Autofix prepared fixes for both issues found in the latest run.

• ✅ Fixed: Missing historical_silo_assignments prevents table drops from executing
  • Added sentry_customdynamicsamplingrule and sentry_customdynamicsamplingruleproject to historical_silo_assignments in router.py with SiloMode.CELL so the SafeDeleteModel DELETE operations can resolve the database and execute DROP TABLE.
• ✅ Fixed: Lockfile not updated for new migration head
  • Updated migrations_lockfile.txt to point to 1065_delete_customdynamicsamplingrule as the new sentry migration head.

Or push these changes by commenting:

@cursor push a55b9dce76

Preview (a55b9dce76)

diff --git a/migrations_lockfile.txt b/migrations_lockfile.txt
--- a/migrations_lockfile.txt
+++ b/migrations_lockfile.txt
@@ -31,7 +31,7 @@
 
 seer: 0005_delete_seerorganizationsettings
 
-sentry: 1064_eventattachment_date_expires_now
+sentry: 1065_delete_customdynamicsamplingrule
 
 social_auth: 0003_social_auth_json_field
 

diff --git a/src/sentry/db/router.py b/src/sentry/db/router.py
--- a/src/sentry/db/router.py
+++ b/src/sentry/db/router.py
@@ -89,6 +89,8 @@
         "sentry_projecttemplate": SiloMode.CELL,
         "sentry_projecttemplateoption": SiloMode.CELL,
         "uptime_projectuptimesubscription": SiloMode.CELL,
+        "sentry_customdynamicsamplingrule": SiloMode.CELL,
+        "sentry_customdynamicsamplingruleproject": SiloMode.CELL,
         "workflow_engine_actiongroupstatus": SiloMode.CELL,
         "workflow_engine_workflowaction": SiloMode.CELL,
     }

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[github-actions]

This PR has a migration; here is the generated SQL for src/sentry/migrations/1065_delete_customdynamicsamplingrule.py

for 1065_delete_customdynamicsamplingrule in sentry

--
-- Delete model CustomDynamicSamplingRuleProject
--
DROP TABLE "sentry_customdynamicsamplingruleproject" CASCADE;
--
-- Delete model CustomDynamicSamplingRule
--
DROP TABLE "sentry_customdynamicsamplingrule" CASCADE;