Implement and enable extra batch selection to ensure one batch per jurisdiction for MD's upcoming pilot audit

[arsalansufi]

Overview

Closes #2259

In preparation for Maryland's upcoming pilot audit, we want to make sure that every jurisdiction in Maryland has at least one batch to audit. The base RLA batch selection logic doesn't guarantee that every jurisdiction has a batch, but we've added extra batches to samples before. Specifically, we add extra batches during every Georgia audit to ensure that every jurisdiction has at least one HMP and BMD ballot batch to audit and that every jurisdiction audits at least 2% of their ballots. For this Maryland pilot use case, the heuristic is much simpler. We just need to add a single batch for every jurisdiction that doesn't have a batch selected by default. The code mirrors the Georgia code.

Testing

• Added an automated test

[arsalansufi]

Correcting a small mistake from when we added support for Maryland's specific style of ES&S CVRs. We only parse those CVRs for the purposes of batch audit file preparation, not ballot comparison audits. This commit just removes the option from the dropdown for latter.