Better handling of unsupported types in args

[mdbenito]

Passing a dataframe / arrow table to any non-scanning clause (LOAD/COPY FROM) results in lb dying in UNREACHABLE_CODE because we hit the end of a switch without handling LogicalTypeId::POINTER, which is what
pyLogicalType maps dfs to, but only for LOAD / COPY ... FROM scan replacement.

This is not a big deal, but I think it's nicer to have an informative error

This PR:

• adds some validation inside the python bindings before expression evaluation happens.
• improves previous checking for "being in a scan query" to also catch LOAD WITH HEADERS.
• adds a few tests (in a separate module since they span polars+pandas+arrow)

[mdbenito]

This looked like a typo

[mdbenito]

The regex should catch all of LOAD, LOAD WITH... and COPY FROM

[adsharma]

The regexes could be replaced to use something like this in C-API:

https://github.com/LadybugDB/ladybug/blob/main/src/c_api/prepared_statement.cpp#L37-L39

That's preferable to using Cypher.g4 and generating python from it and using them so:

# After parsing, check the statement context type  
if isinstance(statement_context, IC_CopyFromContext):  
    # This is a COPY FROM statement  
elif isinstance(statement_context, IC_LoadFromContext):  
    # This is a LOAD FROM statement

because of the maintenance cost (every time the grammar changes, we need to generate bindings)