fix: complying with rust edition 2024 (unsafe_op_in_unsafe_fn)

[sabify]

This PR fixes the Rust code generation to comply with Rust edition 2024 that requires indicating unsafe operations inside unsafe functions.

For reference: https://doc.rust-lang.org/nightly/edition-guide/rust-2024/unsafe-op-in-unsafe-fn.html

[abalmos]

This would be nice to have. Can I help move it forward somehow?

[aleb]

The PR is incomplete, it only handles the Table::new call.
Some others that need to be fixed similarly:

warning[E0133]: call to unsafe function `fbs::flatbuffers::emplace_scalar` is unsafe and requires unsafe block
warning[E0133]: call to unsafe function `fbs::flatbuffers::follow_cast_ref` is unsafe and requires unsafe block
warning[E0133]: call to unsafe function `fbs::flatbuffers::Follow::follow` is unsafe and requires unsafe block
warning[E0133]: call to unsafe function `fbs::flatbuffers::read_scalar_at` is unsafe and requires unsafe block
warning[E0133]: call to unsafe function `fbs::flatbuffers::root_unchecked` is unsafe and requires unsafe block
warning[E0133]: call to unsafe function `fbs::flatbuffers::size_prefixed_root_unchecked` is unsafe and requires unsafe block
warning[E0133]: call to unsafe function `fbs::flatbuffers::Table::<'a>::new` is unsafe and requires unsafe block
warning[E0133]: call to unsafe function `std::slice::from_raw_parts` is unsafe and requires unsafe block

Maybe you can find a way to compile each of the the generated samples, then you will notice all of these.

[aleb]

I needed this, so I made #8638

[fliiiix]

I guess this can be closed as #8638 is merged