[#70168] Fix Session revocation button

[myabc]

Ticket

https://community.openproject.org/work_packages/70168

What are you trying to accomplish?

Use danger-variant button with leading icon to make the action less ambiguous.

Screenshots

Before

After

Merge checklist

• Added/updated tests
• Added/updated documentation in Lookbook (patterns, previews, etc)
• Tested major browsers (Chrome, Firefox, Edge, ...)

[github-actions]

Caution

The provided work package version does not match the core version

Details:

• Work package URL: https://community.openproject.org/work_packages/70168
• Work package version: not set
• Core version: 17.0.0

Please make sure that:

• The work package version OR your pull request target branch is correct

[Copilot]

Pull request overview

This PR improves the session revocation button's UI/UX by replacing an icon-only button with a more prominent danger-styled button that includes both an icon and visible text label. This makes the destructive action more clear and reduces ambiguity.

Key Changes

• Changed from Primer::Beta::IconButton with invisible scheme to Primer::Beta::Button with danger scheme
• Added visible button text using I18n.t(:button_revoke) instead of just an aria-label
• Added a leading visual icon (sign-out) to the button