Use update_column instead of update!

What does this MR do and why?

This MR replaces the project.update!(repository_storage: destination_storage_name) call with project.update_column(:repository_storage, destination_storage_name) from Ensure repository set to writable after moving ... (!136318 - merged).

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #432053