fix(mysql): treat BINARY columns as Blob in Any type mapping

[barry3406]

Does your PR solve an issue?

Fixes #4132

Is this a breaking change?

Yes, this is a breaking behavior change.

Previously, MySQL BINARY(size) columns were mapped through the Any driver to AnyTypeInfoKind::Text, which caused a UTF-8 decoding panic (Utf8Error { valid_up_to: 4, error_len: Some(1) }) when reading raw binary data through AnyRow. After this change, those columns are mapped to AnyTypeInfoKind::Blob and can be decoded as Vec<u8> / &[u8] instead.

Code that previously relied on the (broken) Text mapping and was somehow decoding these columns as strings would need to switch to a binary type, so per Hyrum's Law this should land in the next major release (0.{x + 1}.0).

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MySQL BINARY(size) columns report ColumnType::String with the BINARY flag set. The Any driver's type conversion checked the column type but not the flags, so BINARY columns got mapped to AnyTypeInfoKind::Text. Reading raw binary data through AnyRow then blew up with a UTF-8 decoding error.

Before:

SELECT * FROM test  -- where `id` is BINARY(16)
-- panics: Utf8Error { valid_up_to: 4, error_len: Some(1) }

After:

-- works: BINARY columns correctly mapped to Blob

The fix checks ColumnFlags::BINARY for String/VarString/VarChar column types and maps to Blob when set.

[abonander]

@barry3406 you somehow bypassed the PR template which asks you if there are any breaking changes, and if so, to characterize them. This is a breaking behavior change, so can you please add that to your PR description?