Fix Xiaomi Covers position jumping on stop

[Drafteed]

When the stop command is sent, the currentPositionLiftPercentage of the closuresWindowCovering cluster sending the current position of the curtains.

The problem is that the default converter fz.cover_position_tilt inverses the value and sets incorrect position (xiaomi expect 'open' to be 100, 'closed' to be 0, instead Zigbee specs).

Before

After

[Koenkk]

thanks!