To keep things consistent between the UI and the underlying code, this issue is a follow-up to update any components / variables, etc. that in this context needs changing.
One thing I noticed is that the backend still requires the property name scanner, which it gets from the id property in the filter metadata in the file ee/app/assets/javascripts/security_dashboard/helpers.js, but this is also used for the querystring, so the querystring still uses scanner (e.g. vulnerabilities?scanner=GitLab.SAST&scanner=GitLab.DAST), but the filter name is Tool, which doesn't match.
WDYT about splitting it into two properties, something like id and querystringId? The upside is that then we can set querystringId: 'tool' and it will match the filter name, but the downside is that because the querystring key is changed, it will break any existing bookmarks. We don't have to do it as part of this MR, but I wanted to see what you think of it.
Check the areas of the code that where affected by the renaming and rename instances of variables, methods, etc. that need to be changed to "tool" - this includes some backend changes
Look into the querystring change, which is outlined in the comment by @dftian above
Update specs
Testing
Ensure that all specs where there are references to "scanner" are updated
Counterpart SET to review changes once
Ensure that existing secure E2E tests are not broken by running package and qa as part of merge request(s)