[Feature Request] Add troubleshooting details to

Is your feature request related to a problem? Please describe.

Running the SslEnabledWorkerCustomCASample and forgetting to start the server-sample results in an exception.

Describe the solution you'd like

In the readme - https://github.com/temporalio/samples-java/blob/main/core/src/main/java/io/temporal/samples/ssl/README.md, it would be nice to add a troubleshooting section in the Run SslEnabledWorkerCustomCASample. Even better, modify the sample to catch this error and return a helpful message, like "Did you start the server-sample?"

Example for a troubleshooting section:

5. If you receive an error message similar to

Exception in thread "main" io.grpc.StatusRuntimeException: UNAVAILABLE: io exception

This likely means you forgot to run the server-sample, located here: https://github.com/temporalio/samples-server/tree/main/tls/tls-simple

打开 core/src/main/java/io/temporal/samples/ssl/README.md，从 Run SslEnabledWorkerCustomCASample 的说明开始。添加针对 UNAVAILABLE 异常所要求的故障排查指南，包括 server-sample 的位置和启动要求；完成标准是 README 说明如何诊断此故障。