Go back to forEach in collectcallstats (#2481)

Older typescript library doesn't know about .values() on the stats
object, so it was failing in react sdk which had an older typescript.
matrix-org/matrix-react-sdk#8935 was an
attempt to upgrade it but did not seem to be helping on CI, despite
being fine locally.

Author: dbkr

src/webrtc/call.ts

@@ -708,9 +708,9 @@ export class MatrixCall extends TypedEventEmitter<CallEvent, CallEventHandlerMap
 
         const statsReport = await this.peerConn.getStats();
         const stats = [];
-        for (const item of statsReport.values()) {
+        statsReport.forEach(item => {
             stats.push(item);
-        }
+        });
 
         return stats;
     }