Automatically select DAST profile

What does this MR do?

This reintroduces the changes from !48940 (merged) that had to be reverted because of a bug in mock-apollo-client that broke master. More info about the failure can be found here: #292223 (closed)

Now that the bug has been fixed in the library, we can re-merge those changes with confidence that they won't break master again.

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When there is only a single scanner or site profile available to be selected in the on-demand scan's selectors, that profile will be automatically selected to save the user a few clicks.

How to test this?

1. Make sure you don't have more than one DAST scanner and/or site profile.
2. Open the on-demand scans form at :group/:project/-/security/configuration.
3. The only available profile should be automatically selected in the corresponding dropdown(s).

Screenshots (strongly suggested)

auto_select

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

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

Related to #246892 (closed)