Update blob delete modal

What does this MR do and why?

Update the existing delete blob modal to match new design.

Part 1 of #444302

Implementation breakdown:

Description	MR
update exiting delete blob modal	👈 This MR
use new modal for edit flow	follow-up MR
update doc	!169081 (merged)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

	Before	After
Delete file to current branch and user can push to the branch	Screen Recording 2024-10-11 at 11.26.07 AM.mov	canPush-currentBranch.mov
Delete file to current branch and user can NOT push to the branch How to set up: Make current branch a protected branch and make sure user cannot push to it	Screen Recording 2024-10-11 at 11.24.48 AM.mov	Screen Recording 2024-10-15 at 3.08.43 PM.mov
Delete file to new branch and open a MR	canPush-currentBranch.mov	Screen Recording 2024-10-15 at 2.46.47 PM.mov
Delete file to new branch and NOT open a MR	Screen Recording 2024-10-11 at 11.29.51 AM.mov	Screen Recording 2024-10-15 at 2.47.47 PM.mov
Delete LFS file How to set up: Add a file with Git LFS	Screen Recording 2024-10-11 at 11.30.44 AM.mov	Screen Recording 2024-10-11 at 11.18.44 AM.mov

How to set up and validate locally

1. Open a file in repo
2. Select "Delete"

Related to #444302