fix: update connector client TLS verification

[mxyng]

Summary

Update VerifyConnection function to only output the warning once. Also make it less resource hungry by creating a single CertPool that will be used instead of creating a new CertPool on each VerifyConnection call.

Misc.

Update logging to %v instead of %w

Checklist

• Wrote appropriate unit tests
• Considered security implications of the change
• Updated associated docs where necessary
• Updated associated configuration where necessary
• Change is backwards compatible if it needs to be (user can upgrade without manual steps?)
• Nothing sensitive logged
• Commit message conforms to Conventional Commit
• GitHub Actions are passing

Related Issues

Resolves #1325

[mxyng]

Closing in favour of #1347