fix: Nil panic for InsecureSkipVerify

[MisterMX]

Description of your changes

Fixes a panic due to a nil deref when using a config with InsecureSkipVerify: true.

I have:

• [ ] Read and followed Crossplane's contribution process.
• [ ] Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

[github-actions[bot]]

Successfully created backport PR #127 for release-0.6.