Fix scanner filter not working when report type has no scanner IDs

What does this MR do?

On the vulnerability report, there's a scanner filter dropdown:

Previously, if there are no scanner IDs for one of the shown options, clicking the option will cause the vulnerability list to show all vulnerabilities. This MR fixes it by showing the "your filter produced no results" message:

Please watch this video for a technical explanation on why this happens:

Untitled

and this video on why this solution was chosen:

Untitled

Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Related to #331623 (closed)