Stop trimming mode (internal) only if it is running

Fixes playback stoping on selection change and maybe others

src/monitor/monitor.cpp

@@ -2431,7 +2431,6 @@ void Monitor::processSeek(int pos, bool noAudioScrub)
     if (KdenliveSettings::pauseonseek()) {
         pause();
     }
-    //noAudioScrub = noAudioScrub || pCore->window()->getCurrentTimeline()->controller()->trimmingActive();
     m_glMonitor->requestSeek(pos, noAudioScrub);
     emit m_monitorManager->cleanMixer();
 }

src/timeline2/view/timelinecontroller.cpp

@@ -2183,8 +2183,10 @@ bool TimelineController::requestStartTrimmingMode(int mainClipId, bool onlyCurre
 }
 
 void TimelineController::requestEndTrimmingMode() {
-    pCore->monitorManager()->projectMonitor()->setProducer(pCore->window()->getCurrentTimeline()->model()->producer(), 0);
-    pCore->monitorManager()->projectMonitor()->slotSwitchTrimming(false);
+    if (pCore->monitorManager()->isTrimming()) {
+        pCore->monitorManager()->projectMonitor()->setProducer(pCore->window()->getCurrentTimeline()->model()->producer(), 0);
+        pCore->monitorManager()->projectMonitor()->slotSwitchTrimming(false);
+    }
 }
 
 void TimelineController::addPreviewRange(bool add)