Follow two-step merge request creation process for "Create merge request" within an issue

➡️ See parent epic for more details ⬅️

Problem

• Most Create merge request buttons in the UI open up the create form where the user can fill in the MR details before actually submitting the form
• The Create merge request button within each issue doesn't follow that process; instead, it auto-magically creates the open MR, bypassing the create form entirely. This can be unexpected behavior and is inconsistent with the majority of the buttons.

Proposal

Create merge request should lead to the create form