validator: add Alternator FLOAT32VECTOR type end-to-end tests

[QuerthDP]

Add end-to-end coverage for the Alternator optimized vector type using requests with the new encoding injected into the JSON body.

Verify that queries work for items stored with the optimized vector representation and remain compatible with the existing L-based vector representation in the same index.

Fixes: VECTOR-666

[m-szymon]

1. I was considering adding such tests to types.rs tests (added here #467). I deliberately named it types, not key_types.
2. Adding optimized data to index and querying are slightly separate issues.
3. I was considering defining test datasets using "binary" type and only extending the json injector to convert them to FLOAT32VECTOR when expected - it could better reuse existing utils.

But it works, so consider if you would like to improve anything and we can merge it. I can later refactor.

[QuerthDP]

Changelog:

• rebased on master
• moved tests from query.rs to types.rs
• merged the tests into one, which checks both insert and query

[m-szymon]

It is easier to ask AI to do it, than explain it: 3459c12

The problem is the pk_v_scan is not inserted at scan phase.
I was thinking about adding same trick as @nyh used for Java driver: scylladb/alternator-client-java#87

I also noticed that other test in that file don't actually check returned values. With that fixed, we could extend and use the query_with_key_type function.

[ewienik]

It is easier to ask AI to do it, than explain it: 3459c12

The problem is the pk_v_scan is not inserted at scan phase. I was thinking about adding same trick as @nyh used for Java driver: scylladb/alternator-client-java#87

I also noticed that other test in that file don't actually check returned values. With that fixed, we could extend and use the query_with_key_type function.

@m-szymon Does it mean that something needs to be done in this PR?

[m-szymon]

It is easier to ask AI to do it, than explain it: 3459c12
The problem is the pk_v_scan is not inserted at scan phase. I was thinking about adding same trick as @nyh used for Java driver: scylladb/alternator-client-java#87
I also noticed that other test in that file don't actually check returned values. With that fixed, we could extend and use the query_with_key_type function.

@m-szymon Does it mean that something needs to be done in this PR?

Yes - one small inconsistency that pk_v_scan is not a scan test.
We can either remove/ignore it and enhance tests separately or fix from the beginning.