Fix search bar losing focus while typing, layer height assertions.

[themanyone]

The first commit fixes problems with search dialog:

• Search bar losing focus while typing
• Search results dialog stealing focus even after pressing ESC
• Search results blocking other windows after selection is made
• Navigating the list with arrow keys
• Scroll to the selected item when a search result is clicked

The next commit prevents assertion when switching printer to one that doesn't support current layer height.
#13705

[themanyone]

Working great so far!

[themanyone]

The latest commits work around an assertion in CoolingBuffer that was preventing fuzzy skin in vase mode. #13739

[themanyone]

Save as, Ctrl+Alt+S hotkey was non-functional on Linux. And it is an odd combination to use anyway.
This patch makes Ctrl+Shift+S the "Save as" hotkey. So it is consistent across platforms.
And it also works, which is nice.

[YuSanka]

Thank for your contribution. But please, don't mix several issues into one PR.
We currently work on testing of the initial state of your PR (just first commit)

[themanyone]

Got it. In the future, I will make separate branches for each issue even if it's a small change.