Drop project_settings.allow_editing_commits

project_settings.allow_editing_commits was introduced as part of #287798 (closed) since the feature is no longer going to be used (see &4983 (comment 631424441)), we need to drop the column:

Proposal

Per the Dropping column process we need to split the clean up into three milestones

1. ✅ %14.2 Ignore the column !66754 (merged)
2. ✅ %14.3 Drop the column from database - !68854 (merged)
3. ✅ %14.4 Remove the ignore_column statement from ProjectSetting model !71831 (merged)