Use state of case sensitivity toggle even when find bar isn't open

[njx]

@peterflynn - one line change, plus unit test

For #7040

[peterflynn]

@njx Looks good, just one thought -- should we add a similar unit test for the regexp toggle? Since its state is remembered in a totally different way, might be worth testing separately...

[njx]

Hmmm, I hadn't thought about the regexp toggle. That case seems trickier: if you do Find Next with the find bar closed, it seems like you only want to honor the regexp toggle for the last query you did in the UI itself. If you then change the query somehow (e.g. by using one of the new multiselect methods), it seems like you wouldn't want to honor the regexp toggle.

But it looks like that's actually how it works today. So I can add a unit test for that case just to verify.

(Interestingly, ST seems to get confused in this case...if you do a regexp search with the find bar open, then close it, find next works, but if you then change the query, then open the find bar again, it thinks it's in non-regexp mode even though the regexp toggle is still on.)

[njx]

OK, new unit test added (I also slightly refactored the previous test to make them both more compact). Ready for re-review.

[njx]

er, forgot to tag @peterflynn - ready for re-review

[peterflynn]

Awesome, thanks! Merging.