platform(general): rationalize policy metadata error handling behavior

[mikeurbanski1]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Description

This change causes checkov to fail if the user uses a platform API key, but the connection itself fails (e.g. SSL or auth error), and they don't use --include-all-checkov-checks.

Today, the behavior is that the policy metadata download will fail with an error, but then the run will proceed. However, Checkov thinks all the policies are local policies, and does not run any of them (by design when using an API key). The result is blank output (minus the connection error message in the logs). This causes issues primarily in the IDEs, where there is no error message popup from the failed run, so it just looks like nothing happened.

This change will cause the run to actually fail if no policies are going to get evaluated.

It also handles some general conflicting logic with the use of --skip-download, which causes similar behavior (but without an error).

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my feature, policy, or fix is effective and works (I tested all the cases locally)
• New and existing tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[gruebel]

looks good 🥇