WinRT: emit mediaStatus changes before state changes

This makes sure all mediaStatus changes are emitted, even when some
action is done on the media player as a result of a state change.
Also, when both mediaStatus and state are changed at the same time,
make sure both variables are updated before sending the
corresponding signals.

Task-number: QTBUG-49578
Change-Id: I8eed6692503bba1540070f6435b7ea1f5e25c023
Reviewed-by: Andrew Knight <andrew.knight@intopalo.com>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
Reviewed-by: Christian Stromme <christian.stromme@qt.io>
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@qt.io>