[web-pubsub-client] Migrate to core-websockets

[deyaaeldeen]

Packages impacted by this PR

@azure/web-pubsub-client

Issues associated with this PR

N/A

Describe the problem that is addressed by this PR

Migrates the Azure Web PubSub client to depend on the newly introduced @azure/core-websockets maintaining the current client behavior. In addition, this PR adds the following to facilitate testing:

• a simulator for the Azure Web PubSub WebSocket service.
• a toxic WebSocket proxy that can drop the connection and messages according to the drop probability

What are the possible designs available to address the problem? If there are more than one possible design, why was the one in this PR chosen?

N/A

Are there test cases added in this PR? (If not, why?)

Yes!

Provide a list of related PRs (if any)

#32555

Command used to generate this PR:**(Applicable only to SDK release request PRs)

Checklists

• Added impacted package name to the issue description
• Does this PR needs any fixes in the SDK Generator?** (If so, create an Issue in the Autorest/typescript repository and link it here)
• Added a changelog (if necessary)