fix #294866: The direction of beamed notes does not immediately chang…

…e when the beam is broken

Resolves: https://musescore.org/en/node/294866.

When a ChordRest is removed from its beam during layout, we need to relayout its old beam. This will cause a recalculation of the stem direction, in case it needs to change.

libmscore/chordrest.cpp

@@ -790,6 +790,8 @@ void ChordRest::removeDeleteBeam(bool beamed)
             _beam->remove(this);
             if (b->empty())
                   score()->undoRemoveElement(b);
+            else
+                  b->layout1();
             }
       if (!beamed && isChord())
             toChord(this)->layoutStem();