Core/Movement: correct logic wrongly ported in 2a84562dc8

I'm referencing line 97 from ChaseMovementGenerator.
That commit introduced a modification in this use case:
- Chasing target is not my current victim, I should stop moving till it is my victim again
Changed To:
- Chasing target is not my current vicitm, I should stop chasing
My correction:
- I dont care about the relation of my current victim and my chasing target, I'm commanded to chase, something will tell me to stop chasing
--> Most likely: evade, new attackstart, etc.

the rest are just minor changes

(cherry picked from commit 9080e7863c)

src/server/game/Movement/MovementDefines.cpp

@@ -15,7 +15,6 @@
  * with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "Common.h"
 #include "MovementDefines.h"
 #include "ObjectDefines.h"
 #include "Position.h"