🐛 Fix #150: Reset global handler resolution state when a new GlobalHo…

[greena13]

Context

#150 documents that when a GlobalHotKeys component is mounted, unmounted and then re-mounted, it does not reset the handler resolution state on the second mount (even though the configuration of GlobalHotKeys that it should be using to resolve the handlers has changed).

This issue would likely also arise in a number of other situations where GlobalHotKeys components were being unmounted and remounted or updated - but the situation above is probably the simplest case.

Thanks to the investigation of @StephenHaney and the pull request of @mrlubos (#157) the solution of resetting the handle resolution state every time a new GlobalHotKeys component mounted, presented itself.

This pull request

Simply adds the change suggested above, and resets the handler resolution state whenever a new GlobalHotKeys component mounts.

This is a relatively light-weight operation, as when multiple GlobalHotKeys components are mounting (and the user is not yet pressing any keys) we are effectively clearing empty objects, anyway.

A test has been added that correctly reported the failure condition, and is now passing.

[greena13]

✅⚔️Check the behaviour of this._updateDocumentHandlers() to make sure calling these methods in this sequence will always work as intended.

[greena13]

✅ 🚀See if there is a way of wrapping the resetting of state in this._initHandlerResolutionState() in a condition that will abort resetting the state if it's apparent handler resolution hasn't actually taken place yet, and the state is already set to the default values.