fix(ci): highlight the focused modal button

Description

The confirmation modals shown by glab ci view when cancelling (c) or running (r) a job rendered both buttons identically, so it was not possible to tell which one had focus — the user could not confidently answer the prompt.

This sets an activated style on both modals (SetButtonActivatedStyle with bold + underline + reverse), so the focused button is visually distinct from the unfocused one. Moving the focus with the arrow keys now moves the highlight with it.

Both call sites in internal/commands/ci/view/view.go are covered: the "Are you sure you want to cancel …?" and "Are you sure you want to run …?" modals.

Related Issues

Resolves #3155 (closed)

How has this been tested?

• go build ./internal/commands/ci/view/ — builds clean.
• go test ./internal/commands/ci/view/ — passes.
• gofmt -l internal/commands/ci/view/ — no diff.
• Manually: ran glab ci view against a project with a running pipeline, selected a job, pressed c and r to open both modals, and confirmed the focused button is highlighted and the highlight follows the arrow keys.

The change is purely presentational — no behaviour, flags, or output formats change, so no test or docs updates were needed.

Screenshots (if appropriate):