* Return HTTP 400s on transit decrypt requests where decryption fails. (#10842)

* Don't abort transit batch encryption when a single batch item fails.

* Add unit tests for updated transit batch decryption behavior.

* Add changelog entry for transit encrypt/decrypt batch abort fix.

* Simplify transit batch error message generation when ciphertext is empty.

* Return error HTTP status codes in transit on partial batch decrypt failure.

* Return error HTTP status codes in transit on partial batch encrypt failure.

* Properly account for non-batch transit decryption failure return. Simplify transit batch decryption test data. Ensure HTTP status codes are expected values on batch transit batch decryption partial failure.

* Properly account for non-batch transit encryption failure return. Actually return error HTTP status code on transit batch encryption failure (partial or full).