win-capture: Update hooked state before unhooked signal

[EZ64cool]

Description

Move the game-capture's gc->capturing = false update to before the unhooked signal is sent. This replicates the behaviour of window-capture.

Motivation and Context

If the get_hooked procedure is called during the unhooked signal the source would still report that it's hooked because gc->capturing hasn't been updated yet.

How Has This Been Tested?

Tested on windows 10 x64 and it now works as expected. It's a very isolated change so easy to test.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• [x] My code has been run through clang-format.
• [x] I have read the contributing document.
• [x] My code is not on the master branch.
• [x] The code has been tested.
• [x] All commit messages are properly formatted and commits squashed where appropriate.
• [x] I have included updates to all appropriate documentation.