Never clear QS tile state.

QSTile#clearState puts QS tiles in an invalid state that may not be
immediately rectified through QSTile#refreshState. In the case of
configuration changes, if a subclass implementation of
QSTile#handleSetListening does not trigger a refresh state, the
invalid state causes incorrect click handling.

Change-Id: I17eba133cf08c45a768e9e0ed8fda623e85b4370
Fixes: 69738120
Fixes: 110480955
Test: manual