BytesDictBuilder panics instead of enforcing DictConstraints::max_bytes above 4 GiB

[mnshdw]

What happened?

BytesDictBuilder::encode_value computes the offset of a new entry before checking whether the entry fits under max_bytes

let view = BinaryView::make_view(
    val, 0,
    u32::try_from(self.values.len()).vortex_expect("values length must fit in u32"),
);
let additional_bytes = /* ... */;
if self.dict_bytes() + additional_bytes > self.max_dict_bytes {
    return None;
}

Because the u32::try_from runs first, the builder panics rather than returning None.

We hit this in production

values length must fit in u32:
  Try from int error: out of range integral type conversion attempted

  13: vortex_expect<u32, core::num::error::TryFromIntError>
             at vortex-error/src/lib.rs:347:14
  14: encode_value<u32>
             at vortex-array/src/builders/dict/bytes.rs:110:54
  15: encode_validity<u32, ...encode_varbinview::{closure_env#1}<u32>>
             at vortex-array/src/builders/dict/bytes.rs:180:43
  16: encode_varbinview<u32>
             at vortex-array/src/builders/dict/bytes.rs:253:14

Steps to reproduce

let values = VarBinViewArray::from_iter_str(
    (0..4_300_000).map(|i| format!("{i:08}{}", "x".repeat(1016))),
)
.into_array();
dict_encode(&values, &mut ctx).unwrap(); // panics

Environment

• Vortex develop @ 68e2aee0a
• Rust 1.98.0

Additional context

No response