Address edge cases resulting from the MR query author or assignee

Proposal

Make it a preference to opt in that the MR homepage includes "authored or assignee" #547449 (comment 2541446492)

Other considerations

1. Hide draft merge requests
2. Put draft merge requests into an inactive list
3. Inform user about the change of count on the MR homepage

It wouldn't be all that annoying if I could set Draft: and have that ignored in the list, but that doesn't work (I already have a few drafts showing up in the list).

Background

When we turned on the feature flag merge_request_dashboard_author_or_assignee, it caused a disruptive shock to people's workflows.

Sudden increase in merge request counts

@andr3 From 2 => 19! Oh boy.....

@dianalogan 😅 29 MRs in my queue. I remember this happened a while ago from the TW test project, but I'm not clear on why these MRs have suddenly reappeared.

Existing authored MRs may never be closed

@marcel.amirault A separate issue is that I sometimes create test MRs to validate issues, but I want to keep them open so that others who are reading through old issues can still access the test MR. For example, this MR is demonstrating pipelines with specific edge case job names. It's for a related issue that has not been completed yet, but it's still going to be worked on eventually. I don't want to close it, but am not working on it and will not be assigning anyone to it. It wouldn't be all that annoying if I could set Draft: and have that ignored in the list, but that doesn't work (I already have a few drafts showing up in the list).

Show more button not working

@marcel.amirault For me, the Show more button doesn't seem to work. I wanted to check if there were any MRs were I was neither the Author or Assignee, but I'm unable to check the next page without closing the first 20 MRs. I just get :spinner: forever.