crosscluster/logical: support replicating table with composite type in pk

Examples of Composite Types: Decimals, Collated Strings

Technical Justification: Decoding a primary key with a composite type requires reading the current value. When the rangefeed sends over a delete, however, we do not see the current value. While we could rely on the prev value sent over the rangefeed, we currently have no way to handle phantom deletes (i.e. a delete on a key with no previous value)
There are also complications around column families, but let’s ignore that for now, as we disallow replicating tables with column families.

Jira issue: CRDB-43692

Start by tracing the crosscluster/logical replication path for primary-key decoding and rangefeed deletes. Investigate how composite types, current values, previous values, and phantom deletes are handled, while confirming that column-family tables remain excluded. Done means tables with composite types in their primary keys can replicate correctly, including deletes.

Written by the indexing model from the issue text.