Robust validation of ClientOpts for Kong admin API client

[programmer04]

Is there an existing issue for this?

• I have searched the existing issues

Does this enhancement require public documentation?

• I have added an Acceptance Criteria item for adding and/or adjusting public documentation (if applicable)

Problem Statement

The PR

• feat: deprecate --gateway-discovery-dns-strategy - make discovery always work #7033

reworked client and initially introduced validation to not allow mutually exclusive options to be set, see

1a6f7cc#diff-540e5a66571fe7ea83c6641fb9bc48b485ee07dce80a1f28de9ddccd2bf77d0c

but it breaks the Ingress Chart, which sets paths for certs, and TLSSkipVerify option too (which takes precedence).

Read for more context #7033 (comment)

Proposed Solution

When Ingress Chart compatibility won't be a problem (e.g. moving this to KO), bring back 1a6f7cc#diff-540e5a66571fe7ea83c6641fb9bc48b485ee07dce80a1f28de9ddccd2bf77d0c the change

Additional information

No response

Acceptance Criteria

• setting mutually exclusive (overlapping) options for TLS is forbidden and reports an error on startup (this is exactly what the aforementioned change had made)