Remove feature flag import_rescue_query_canceled
What does this MR do and why?
The feature flag import_rescue_query_canceled was introduced in !191628 (merged) and globally rolled out on June 2, 2025 at 2:28:44 PM GMT+2.
This MR removes the feature flag.
About the feature
Feature flag :import_rescue_query_canceled enables retry mechanism for database timeouts during Direct Transfer imports
This feature flag controls the retry logic in RelationObjectSaver that handles ActiveRecord::QueryCanceled exceptions. When enabled, it automatically retries failed batches with smaller sizes (up to 3 attempts) instead of stopping the import process, preventing data loss during nested record imports like notes, diff notes, and events.
References
How to set up and validate locally
You can verify that the feature works as before by following the validation steps in !191628 (merged)
MR acceptance checklist
Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.
Related to #547264