feat(stacktrace): Add stacktrace improvements feature flag (#52983)

Closes #52591

Add a feature flag to toggle new improvements to the issue details
stacktrace ui.

Author: Julia Hoge

src/sentry/conf/server.py

@@ -1621,6 +1621,8 @@ def SOCIAL_AUTH_DEFAULT_USERNAME() -> str:
     "organizations:anr-rate": False,
     # Enable tag improvements in the issue details page
     "organizations:issue-details-tag-improvements": False,
+    # Enable updates to the stacktrace ui
+    "organizations:issue-details-stacktrace-improvements": False,
     # Enable the release details performance section
     "organizations:release-comparison-performance": False,
     # Enable team insights page

src/sentry/features/__init__.py

@@ -91,6 +91,7 @@
 default_manager.add("organizations:issue-details-replay-event", OrganizationFeature, FeatureHandlerStrategy.REMOTE)
 default_manager.add("organizations:issue-details-most-helpful-event", OrganizationFeature, FeatureHandlerStrategy.REMOTE)
 default_manager.add("organizations:issue-details-tag-improvements", OrganizationFeature, FeatureHandlerStrategy.REMOTE)
+default_manager.add("organizations:issue-details-stacktrace-improvements", OrganizationFeature, FeatureHandlerStrategy.REMOTE)
 default_manager.add("organizations:issue-platform", OrganizationFeature, FeatureHandlerStrategy.REMOTE)
 default_manager.add("organizations:issue-search-allow-postgres-only-search", OrganizationFeature, FeatureHandlerStrategy.REMOTE)
 default_manager.add("organizations:issue-search-use-cdc-primary", OrganizationFeature, FeatureHandlerStrategy.REMOTE)