Expand test coverage for veres-one-validator when replacing MOCKPROOF

[aljones15]

We have tests for when the invocationTarget doesn't match, but we need tests for when you have the wrong root capability.

We need tests that hit this check in zcapld: https://github.com/digitalbazaar/zcapld/blob/e655ba0e67cbbf8d72467e7d650365bbe936a1c3/lib/utils.js#L522-L525

Also, we have no tests for the first proof in a record write operation because it is currently a MOCKPROOF.
When we remove the MOCKPROOF for a real ledgerWrite proof we need to also add a set of tests that ensure that ledgerWrites fail if

• The invocationTarget has the wrong <incorrect-ledgerId>/records
• The invocationTarget has a unknown path <ledgerId>/unknown
• The capability id for the ledgerWrite proof is invalid capability: urn:zcap:invalid:foo
• The capability id for the ledgerWrite proof refers to a non-existent ledger (this might succeed) urn:zcap:root:did:non:existent:ledger