fix(aci): Don't acquire lock if issue alert dual write is disabled (#92371)

Make the lock acquisition a no-op when dual write is disabled.
The locking is there to avoid duplicates being created when trying to
get a default error detector; but we only do that for dual write.
Being able to avoid the lock is important, as some users are seeing
consistent errors from failing to acquire the lock under concurrent
load, and we'd like opting out of dual write to mitigate the problem for
them while we fix the underlying issue.

Author: kcons

src/sentry/projects/project_rules/creator.py

@@ -1,7 +1,8 @@
+import contextlib
 import logging
-from collections.abc import Sequence
+from collections.abc import Callable, Sequence
 from dataclasses import dataclass
-from typing import Any
+from typing import Any, ContextManager
 
 from django.db import router, transaction
 from rest_framework.request import Request
@@ -34,13 +35,21 @@ class ProjectRuleCreator:
     request: Request | None = None
 
     def run(self) -> Rule:
-        try:
+        # Only acquire a lock if issue alert dual write is enabled.
+        lock_acquire: Callable[[], ContextManager[None]] = lambda: contextlib.nullcontext()
+        if features.has(
+            "organizations:workflow-engine-issue-alert-dual-write",
+            self.project.organization,
+        ):
             lock = locks.get(
                 f"workflow-engine-project-error-detector:{self.project.id}",
                 duration=10,
                 name="workflow_engine_issue_alert",
             )
-            with lock.acquire(), transaction.atomic(router.db_for_write(Rule)):
+            lock_acquire = lock.acquire
+
+        try:
+            with lock_acquire(), transaction.atomic(router.db_for_write(Rule)):
                 self.rule = self._create_rule()
 
                 if features.has(