Remove CLI ca-file requirement for sandbox connections.

[calohmn]

Follow-up of #3570:
The CLI --ca-file parameter shouldn't be required when connecting to the sandbox.

[sophokles73]

GraalVM 21 copies the JDK's cacerts into the executable at build time. Thus, if the root CAs expire or get revoked etc, it will still be necessary to specify the trusted certs store on the command line. Anyway, for the JRE based version, this will most likely work as expected and for the native executable the --ca-file parameter can still be used.
@calohmn Maybe you could add some corresponding wording to the documentation?

[calohmn]

@sophokles73 I've added a corresponding note in the "Getting Started" guide.

[sophokles73]

LGTM