feat(windows): right modifer keys include in hotkey if configured

[rc-swag]

Fixes:#11471

[keymanapp-test-bot]

User Test Results

Test specification and instructions

ERROR: user tests have not yet been defined

[rc-swag]

@mcdurdin
I got it wrong around the removal of two old flags not fully understanding that there was interaction with a Win32 API RegisterHotkey. I had removed the caching code and I had also handled including the right modifier based on the user flag. However, I did not realise that the RegiserHotkey interaction with the win32 api was still occurring. I have partly fixed it.
However, I need to check the way I should be going forward.
Is it to use the RegisterHotkey API call on right modifier inclusion still? Or is it to totally remove the use of the RegisterHotkey, and just use the keyman engine implementation and just setting testing for right modifier when the flag is set? I think it is the later.

[mcdurdin]

@rc-swag as discussed in Standup, go ahead and remove all the code that is bracketed by the compatibility flags, including RegisterHotkey calls, and then add support for left-side modifiers to the remaining hotkey management system.