More gracefully handle missing claim and missing fullUrl

[tstrass]

Summary

Issue: In the client suite, we were return a 500 "low level error occurred" in the event that a claim submission was missing a claim or if the claim was missing a fullUrl (which are both required in the spec). The claim validation test also resulted in an inferno error if there was no fullUrl.

Resolution: Add a check to avoid a 500, return a 400 with an appropriate OperationOutcome instead. Also add safe navigation in the validation module to avoid an inferno error in the validation test.

Testing Guidance

Run a $submit test. Send it a bundle without a claim. Sent it a bundle with a claim that is missing a fullUrl.

[karlnaden]

in the case that a 400 error is returned, the attestation test should skip rather than ask for the attestation since we didn't send the actual response back.

[karlnaden]

let's take the opportunity to add rspec tests for the submit tests that verify this functionality

[karlnaden]

skip update looks good. Will defer unit tests to later (see FI-2761)