Split AlertTable into smaller components

[robertbrignull]

Refactors the rendering in AlertTable. Previous it was multiple nested foreach loops adding components to a rows array from multiple places, including the rendering of zero results or truncated results. As of this PR it's a series of hierarchical components.

Each small change is done as a separate commit, so theoretically you should be able to follow along with them. Or it may be easier to review the end result on its own if that's what you prefer.

I've tried to test manually and as far as I can tell, everything looks and behaves exactly the same as before 🎉

Checklist

• CHANGELOG.md has been updated to incorporate all user visible changes made by this pull request.
• Issues have been created for any UI or other user-facing changes made by this pull request.
• [Maintainers only] If this pull request makes user-facing changes that require documentation changes, open a corresponding docs pull request in the github/codeql repo and add the ready-for-doc-review label there.

[charisk]

LGTM in general although I can't promise I've gone through every line and character change since there is a fair bit of code moving around. I think there are a couple of cases where we're using useMemo when we should be using useCallback (unless I misread the code) but otherwise LGTM!

Thanks for making this better gradually - it's great to see the individual components now.

[robertbrignull]

Thank you @charisk for the review. For the handleDropdownClick methods it was a simple case of switching the useCallback. For the handleSarifLocationClicked methods, it required doing the same adjustment to updateSelectionCallback that I already did to toggle, so it isn't using "nested methods". Thank you for pointing out that improvement.