Fix toggleCapsLock failed for multiple EventHub devices

If a physical device includes multiple EventHub devices for different
funcions, it would also create multiple InputMappers to process raw
events. And it may contain multiple KeyboardInputMapper.

When 'toggleCapsLock' called, we have to check if device has the meta
state key such as CAPS_LOCK or NUMS_LOCK, then we should just update the
the first InputMapper that own the meta state key to prevent other
InputMapper update the global state multiple times.

Bug: 195405545
Test: atest inputflinger_tests
Test: shortcut key META-ALT
Change-Id: I9d09e13d1de416370b8570b6621db5c4bf1ba8eb