Fix exit frame handling for "PlayAll" playback mode

Without this when the playback cue is on the highest frame in "PlayAll"
mode it doesn't take into account the direction of the current tag that
is being played and assumes the end of the animation was reached

src/doc/playback.cpp

@@ -244,6 +244,8 @@ bool Playback::handleExitFrame(const frame_t frameDelta)
           }
           break;
         }
+        else if (m_playMode == PlayAll)
+          break;
       }
 
       if (frameDelta > 0 && m_frame == m_sprite->lastFrame()) {