New file modal: Use commit changes UI
Proposal
During a discussion #444302 (comment 2158381424), designs were updated for the commit changes modal. For consistency, the changes made in !170512 (comment 2189831074) need to be percolated to the Edit file, Delete file, New file, Upload file, and New directory flows.
- Replace the "Start a new merge request with these changes" toggle with the checkbox UI from the commit changes modal.
| Current | Proposed | 
|---|---|
Problem
When you go to create a new directory, the UI to commit changes appears at the bottom of the page and is not using the commit changes modal. This is inconsistent with the changes made to the edit file blob in !170512 (merged) and #444302 (closed).
Steps
- Go to "Code > Repository"
- Click on the "+"
- Click on "New file"
Scenarios
The following conditions should be considered (see !170512 (merged)):
- Commit to the current branch and user can push to the branch
- Commit to the current branch and user can NOT push to the branch
- Commit to new branch and open a MR
- Commit to new branch and NOT open a MR
- Add an LFS file
- Cancel button pops a confirmation modal
- Mobile screen
Related UI
These are areas of the UI that should all be using the same commit changes modal UI:
| UI element | Issues/MRs | Reproduction steps | 
|---|---|---|
| Edit file | !170512 (merged) (in review) | Code > Repository > Select a file > Edit > Edit single file | 
| Delete file | #503405 (closed) (open) | Code > Repository > Select a file > Delete | 
| New file | #502460 (closed) (this, open) | Code > Repository > New file | 
| Upload file | #479249 (closed) (open) | Code > Repository > Upload file | 
| New directory | #502483 (closed) (open) | Code > Repository > New directory | 



