ref(TPC): Cleanup flags related to low fps screenshare.

Simulcast for SS is always on in unified plan mode, the lower spatial resolution streams are turned off for low fps sharing.

modules/RTC/TraceablePeerConnection.js

     this.statsinterval = null;
 
     /**
-     * Flag used to indicate if simulcast is turned off and a cap of 500 Kbps is applied on screensharing.
+     * Flag used to indicate if low fps screenshare is desired.
      */
     this._capScreenshareBitrate = this.options.capScreenshareBitrate;
 

modules/xmpp/JingleSessionPC.js

             pcOptions.disableSimulcast
                 = options.disableSimulcast || options.videoQuality?.preferredCodec === CodecMimeType.H264;
 
-            // Disable simulcast for low fps screenshare and enable it for high fps screenshare.
-            // testing.capScreenshareBitrate config.js setting has now been deprecated.
+            // Do not send lower spatial layers for low fps screenshare and enable them only for high fps screenshare.
             pcOptions.capScreenshareBitrate = pcOptions.disableSimulcast
                 || !(typeof options.desktopSharingFrameRate?.max === 'number'
                     && options.desktopSharingFrameRate?.max > SS_DEFAULT_FRAME_RATE);
-
-            // add the capScreenshareBitrate to the permanent properties so that it's included with every event that we
-            // send to the analytics backend.
-            Statistics.analytics.addPermanentProperties({ capScreenshareBitrate: pcOptions.capScreenshareBitrate });
         }
 
         if (options.startSilent) {