Allow cursor to be updated while connecting

We haven't got a server provided cursor at this point, but we might
have done something local, e.g. enabled the dot cursor.

kasmweb/core/rfb.js

@@ -2071,7 +2071,10 @@ export default class RFB extends EventTargetMixin {
     }
 
     _refreshCursor() {
-        if (this._rfb_connection_state !== 'connected') { return; }
+        if (this._rfb_connection_state !== "connecting" &&
+            this._rfb_connection_state !== "connected") {
+            return;
+        }
         const image = this._shouldShowDotCursor() ? RFB.cursors.dot : this._cursorImage;
         this._cursor.change(image.rgbaPixels,
                             image.hotx, image.hoty,