Add link to settings from within Merge request area
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### Proposal
To help users get to settings from Merge requests there should be link to get to it from the merge requests area.
The boring solution is to introduce the `link in the submenu` because this could also be relevant to other product areas like Repository as well.
#### Explorations
| Link in submenu | Link in page as an icon button | Link close to widget |
| ------ | ------ | ------ |
|  |  |  |
#### Related research
This concept of having links to "settings" was explored in this solution validation https://gitlab.com/gitlab-org/ux-research/-/issues/1306#note_506613378
Explored was navigating to "Settings" from Repository and Merge requests and most participants used the "Settings" link in the submenu ([Insights summary](https://dovetailapp.com/projects/011ea00e-71fc-4dce-9562-438055b8e9e8/insights/present/582d31cf-8cbf-48cc-a217-18ac9c26063e))
issue