Refactor EthStatsService creation of WebSocket

[macfarla]

Vertx has deprecated HttpClient.webSocket() methods
it's now a separate class - https://vertx.io/docs/guides/vertx-5-migration-guide/

Refactor EthStatsService and EthStatsServiceTest to use the new class

> Task :ethereum:ethstats:compileJava
Note: /workspace/b2/ethereum/ethstats/src/main/java/org/hyperledger/besu/ethstats/EthStatsService.java uses or overrides a deprecated API.

Acceptance criteria:

• no deprecation warnings when compiling this module

[vitamin43]

Hi, I would like to work on this issue. Could you please assign it to me?

[macfarla]

go for it @vitamin43 - any questions you can ask on this issue or in our discord https://discord.com/channels/905194001349627914/938504958909747250

[KYash03]

Hi @macfarla - I apologize for the overlap, but I had already started working on this issue before the assignment to @vitamin43. Here's my PR: #8327

[macfarla]

Thanks @KYash03 looks promising, someone will review.

@vitamin43 don't want to waste your time - have a look at other good first issues