fix(realtime): updated the worker clearance in the _startWorkerHeartBeat function

Previously, the worker error handler in _startWorkerHeartbeat() directly calledworkerRef.terminate()
without clearing the workerRef reference. This caused amemory leak on worker errors because on
reconnection, the guard check for workerRef would prevent creating a new worker, leaving the
connection withouta heartbeat mechanism.Now uses the centralized _terminateWorker() method which
both terminates theworker and clears the reference, ensuring proper cleanup and allowing newworkers
to be created on reconnection.This complements the fix in _teardownConnection() to fully prevent
workermemory leaks across all disconnect/error scenarios.

Author: Tanmay Sharma

packages/core/realtime-js/src/RealtimeClient.ts

@@ -699,7 +699,7 @@ export default class RealtimeClient {
     this.workerRef = new Worker(objectUrl)
     this.workerRef.onerror = (error) => {
       this.log('worker', 'worker error', (error as ErrorEvent).message)
-      this.workerRef!.terminate()
+      this._terminateWorker()
     }
     this.workerRef.onmessage = (event) => {
       if (event.data.event === 'keepAlive') {