[layouts] use gray icons for the items panel

Author: nirvn

images/images.qrc

@@ -321,6 +321,7 @@
         <file>themes/default/mActionSharingExport.svg</file>
         <file>themes/default/mActionSharingImport.svg</file>
         <file>themes/default/mActionShowAllLayers.svg</file>
+        <file>themes/default/mActionShowAllLayersGray.svg</file>
         <file>themes/default/mActionShowBookmarks.svg</file>
         <file>themes/default/mActionShowHideLabels.svg</file>
         <file>themes/default/mActionShowPinnedLabels.svg</file>

images/themes/default/lockedGray.svg

@@ -248,11 +248,11 @@ QVariant QgsLayoutModel::headerData( int section, Qt::Orientation orientation, i
     {
       if ( section == Visibility )
       {
-        return qVariantFromValue( QgsApplication::getThemeIcon( QStringLiteral( "/mActionShowAllLayers.svg" ) ) );
+        return qVariantFromValue( QgsApplication::getThemeIcon( QStringLiteral( "/mActionShowAllLayersGray.svg" ) ) );
       }
       else if ( section == LockStatus )
       {
-        return qVariantFromValue( QgsApplication::getThemeIcon( QStringLiteral( "/locked.svg" ) ) );
+        return qVariantFromValue( QgsApplication::getThemeIcon( QStringLiteral( "/lockedGray.svg" ) ) );
       }
 
       return QVariant();