Fix faulty IP address DNS check

[dylan-stella]

Related Issue

#1444

New Behavior

Check for no IP address being available

Contrast to Current Behavior

Current behavior breaks inventory sync if the primary IP is not on one of the interfaces when checking for DNS. If you're not using the DNS feature, then this is the same as having None.

Discussion: Benefits and Drawbacks

This breaks our inventory sync periodically when there is dirty data left behind in our Netbox. Since we're not using the DNS feature and we don't need to check.

However, this will hide the issue where the primary IP is not on any interface.

Changes to the Documentation

None

Proposed Release Note Entry

Fix sync error when primary IP address not on interfaces

Double Check

• I have read the comments and followed the CONTRIBUTING.md.
• I have explained my PR according to the information in the comments or in a linked issue.
• My PR targets the devel branch.

[sc68cal]

Hi, thanks for the contribution. If you could please create a changelog fragment, that would get CI passing. These are required so that we can generate release notes (and give you credit) when we create a new release

[sc68cal]

The linting failure, I think it's because black pushed a new version with some new rules. You will need to rebase, once it is fixed