movement: convert can_sleep an automatic variable

It is a simple boolean value and its scope is limited to the function.
There is no reason that I can think of for it to be a static variable.

movement/movement.c

@@ -509,7 +509,7 @@ bool app_loop(void) {
     }
 
     // default to being allowed to sleep by the face.
-    static bool can_sleep = true;
+    bool can_sleep = true;
 
     if (event.event_type) {
         event.subsecond = movement_state.subsecond;