feat: migrate survey prompts to huh (phase 2)

Description

• feat: migrate survey prompts to huh (phase 2)

Related Issues

Resolves #8031 (closed)

How has this been tested?

mr update - "Proceed with changes" / "Cancel" prompt

This prompt appears when you use the --fill flag without --yes:

# This will show the new huh.NewConfirm() prompt with "Proceed with changes" / "Cancel"
./bin/glab mr update <MR_ID> --fill

What to expect:

1. It will show "Proposed changes" with the autofilled title/description
2. You'll see a prompt: "What would you like to do?"
3. Navigate with left/right arrow or tab between:
   1. "Proceed with changes" (affirmative)
   2. "Cancel" (negative)
4. Press Enter to confirm your choice
5. Try pressing Ctrl+C to test cancellation handling

Example:

# Using an MR from your current branch
./bin/glab mr update --fill

# Or with a specific MR number
./bin/glab mr update 123 --fill

Screenshots (if appropriate):