fix #306726 Screen readers: Restore speech during note input

Fixes an accessibility bug in commit 3960396 in PR #6173 that caused
the screen reader to say "note input mode" periodically rather than
just once upon entering that mode. This interfered with the usual
screen reader output for that mode.

Also displays mode text for "Normal mode".

mscore/musescore.cpp

@@ -4272,10 +4272,11 @@ void MuseScore::inputMethodVisibleChanged()
 
 void MuseScore::showModeText(const QString& s)
       {
+      if (s == _modeText->text())
+            return;
       if (cs)
             cs->setAccessibleMessage(s);
       _modeText->setText(s);
-      _modeText->show();
       }
 
 //---------------------------------------------------------
@@ -4389,7 +4390,7 @@ void MuseScore::changeState(ScoreState val)
                   showPianoKeyboard(false);
                   break;
             case STATE_NORMAL:
-                  _modeText->hide();
+                  showModeText(tr("Normal mode"));;
                   break;
             case STATE_NOTE_ENTRY:
                   if (cv && !cv->noteEntryMode())