feat: allow running rdev in a thread

[Pranav2612000]

What does this PR do?

• This PR allows us to capture events on a non-main thread. At the moment, the rdev crate only works if run on the main thread.

Why do we need this change?

• At the moment, the listen loop runs using CFRunLoopGetMain which returns the loop of the main thread. This causes problems if rdev listen is called in a non-main thread.
• We replace CFRunLoopGetMain with CFRunLoopGetCurrent which returns the loop of the current thread. This seems to fix the issue. This is also the way its done in the original rdev crate LINK

Gotcha's

• The PR and other explanations are based on the understanding of the difference between CFRunLoopGetCurrent vs CFRunLoopGetMain which fixes the issue.

[HuakunShen]

But using CFRunLoopGetCurrent will result in a crash in Tauri apps when keyboard is pressed. Not sure why that happens, using CFRunLoopGetMain solves the problem, but in exit_grab, CFRunLoopStop(CUR_LOOP); could not kill the loop.