MediaNavigationBar: Adjust close button behavior

This merge request brings some adjustments to the close button's behavior.

For the audio player:

• The single press action will minimize the player
• The long press action will close the player

The button's icon and action are also upated when the playback state changes:

• When the media is being played, the button's action will minimize the player
• When the media is paused, the button's action will close the player

For the video player:

• The single press action will close the player
• The long press action will minimize the player

Long press actions will display the status label stating the action that will be performed: the minimizing or the closing of the player.

Closes #1453 (closed)