Allow ability to schedule a merge from merge widget
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From https://gitlab.com/gitlab-org/gitlab/-/issues/14380#note_2166197932
In reviewing the work by @Taucher2003 for https://gitlab.com/gitlab-org/gitlab/-/merge_requests/165250 I can see that we now have something that works that aligns to the "merge after" approach :thumbsup:.
One of the limitations I ran into during the review of the feature was that if I needed to reschedule or delete the scheduled merge request there was no way to do this.
To solve that this alternative approach looks at putting the scheduling functionality in the merge check widget area as a dropdown option on the "Set as auto-merge" button. This is similar to "Merge immediately" functionality with the "Merge" button. FYI @phikai
[](https://gitlab.com/gitlab-org/gitlab/-/issues/14380/designs/schedule_merge_from_merge_request_widget.png)
### Video of concept

## Inspiration
This concept inspired by the comments by @blown2bytes and @JoeIzzard
From https://gitlab.com/gitlab-org/gitlab/-/issues/14380#note_2079357130
> The way I envision it this "scheduled merge" is just an extension of the existing auto-merge feature.
From https://gitlab.com/gitlab-org/gitlab/-/issues/14380#note_2079836821
> I see this request more along the lines of email or communication apps where you can schedule the message to be sent. Where you have the merge button, you maybe have a dropdown and can select schedule instead sort of thing. Up until it actually sends, you can alter the MR, doing so would cause all the checks to re-run etc, and if they still pass then it can carry on.
issue