Migrate Deploy Keys Confirmation Modal to GitLab UI

What does this MR do?

A start at improving the modal to remove deploy keys from a base confirmation, to make it clearer of the side effects of removing the key.

Upgrade buttons and links to use GitLab UI components for consistency.

For #231474 (closed).

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

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  • I have not included a changelog entry because _____.
• Documentation (if required)
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Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team