Allow right clicking outside of image to close it

TODO.md

@@ -8,7 +8,6 @@
     - buttons 
     - keyboard controls
     - prevent drag-scrolling timeline when image opened
-    - right click in dark space of image viewer
 
 - clipboard preview doesn't update when copied image changes until second time
 - Avatar tooltip can get displayed in front of presence menu

src/gui/Popups/ImageViewerPopup.qml

@@ -58,6 +58,7 @@ HPopup {
         ScrollBar.vertical: null
 
         TapHandler {
+            acceptedButtons: Qt.LeftButton | Qt.RightButton
             onTapped: popup.close()
             gesturePolicy: TapHandler.ReleaseWithinBounds
         }