…ad (#69872)

### What problem does this PR solve?

Issue Number: close #69858

Related PR: None

Problem Summary:

The shared Arrow BOOLEAN and DECIMAL SerDes dereference unchecked
`dynamic_cast` results. Passing an `Int32Array` to the BOOLEAN reader or
a `StringArray` to the DECIMAL64 reader can therefore terminate the BE
instead of returning a load error. MAP and STRUCT have the same
unchecked input-cast pattern.

Reject incompatible arrays before accessing buffers, decimal metadata,
or values, independently of `enable_arrow_input_validation`. Reject
mismatched STRUCT field counts before indexing children. Add the column
name and source/destination types to V1/V2 Arrow load errors.

The current V2 Stream Load reader already binds supported input types
with safe Arrow casts. Preserve those conversions, including valid
integer-to-BOOLEAN and string-to-DECIMAL inputs, and test the shared
SerDes directly for incompatible arrays.