Translate slot invalidation failures to appropriate error code

[msfstef]

As of PG18, slot invalidation errors come through with an invalidation reason that we should parse and translate into an appropriate explanation in our custom errors so that users can action them.

There is a list of explanations in the PG codebase we can adapt, thank you @alco for digging for them. See https://github.com/electric-sql/electric/pull/3321 for the rest of the discussion on this issue.