fixed: wrong screen share button state when screen sharing aborted

src/lib/VueJanus.vue

@@ -245,6 +245,9 @@
                 }
             },
             onlocalstreamScreen (stream) {
+                if(this.screenShareStarted)
+                    this.screenShareStarted=false;
+
                 this.$refs.ownstreamscreen.srcObject = stream
             },
             screenShareSwitch () {
@@ -279,8 +282,6 @@
                 var unpublish = { request: 'unpublish' };
                 this.janusScreenShareHandle.send({ message: unpublish });
                 this.janusScreenShareHandle.detach();
-
-                this.screenShareStarted=false;
             },
             screenShare () {
                 if(!this.$janus.isExtensionEnabled()) {