Track leverage of #562 for 3rd-party imports.

[allenrobel]

Summary

This issue tracks migration of 3rd-party import guard handling to leverage the technique described in PR #562 .

Some PRs and/or issues listed below can utilize this. We can add more as appropriate.

• Resolving sanity errors in base collection without ignore #539
• dcnm_vrf_v2: Pydantic integration (replaces #400) #550