fix accidentals in key changes for JustifiedMusicSystemBuilder (#104)

src/MusicalScore/Graphical/MusicSystemBuilder.ts

@@ -504,6 +504,7 @@ export class MusicSystemBuilder {
             }
         }
         measure.InitiallyActiveClef = currentClef ?? this.activeClefs[visibleStaffIdx];
+        measure.resetLayout(); // (only) needed for JustifiedMusicSystemBuilder
         if (isSystemStartMeasure) {
             if (!currentClef) {
                 currentClef = this.activeClefs[visibleStaffIdx];