Select MWPS on MR Creation UI

Release notes

Problem to solve

Often times, simple changes to projects should just be merged as soon as the pipeline passes. This is very true for small handbook changes, especially to pages where the MR author is the page owner, or to code projects that you own.

Today, you can set a MR to merge when the pipeline succeeds, but it requires the MR to be created and the initial CI checks to execute before the button to MWPS becomes clickable. This can often be frustrating as users are forced to sit around and wait for this button to be clickable.

Likely, the user knows during MR creation that they would like something to MWPS. We already have a section for Merge options, and should add an option to MWPS to that section.

Proposal

Add an option to Merge options in the MR creation UI titled "Automatically merge when the pipeline succeeds."