Fix crash on lasso selection

In the case of a lasso selection, `interaction->selection()->element()` is (or can be) nullptr.

src/notation/view/notationviewinputcontroller.cpp

@@ -908,10 +908,16 @@ void NotationViewInputController::mouseReleaseEvent(QMouseEvent* event)
     m_isCanvasDragged = false;
 
     if (interaction->isDragStarted()) {
+        bool isDraggingHairpinSegmentGrip
+            = interaction->isGripEditStarted()
+              && interaction->selection()->element()
+              && interaction->selection()->element()->isHairpinSegment();
+
         interaction->endDrag();
+
         // When dragging of hairpin ends on a note or rest, open dynamic popup
         // Check for note or rest happens in Score::addText which is called through addTextToItem in toggleDynamicPopup
-        if (interaction->selection()->element()->isHairpinSegment()) {
+        if (isDraggingHairpinSegmentGrip) {
             interaction->toggleDynamicPopup();
         }
     }