[BUG] as_type cast from 'uint16_t' (aka 'unsigned short') to 'bfloat16_t' (aka '_MLX_BFloat16') is not allowed

[madrob]

Describe the bug

In file included from /Users/runner/actions-runner/_work/mlx/mlx/mlx/backend/metal/kernels/unary.metal:5:
In file included from /Users/runner/actions-runner/_work/mlx/mlx/mlx/backend/metal/kernels/unary_ops.h:11:
/Users/runner/actions-runner/_work/mlx/mlx/mlx/backend/metal/kernels/fp8.h:75:12: error: as_type cast from 'uint16_t' (aka 'unsigned short') to 'bfloat16_t' (aka '_MLX_BFloat16') is not allowed
    return as_type<bfloat16_t>(out);
           ^~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[2]: *** [mlx/backend/metal/kernels/unary.air] Error 1
make[2]: *** Waiting for unfinished jobs....

To Reproduce
https://github.com/ml-explore/mlx/actions/runs/19045287880/job/54391897854#step:5:4384

Expected behavior
Compilation to succeed

Desktop (please complete the following information):

• OS Version: 15.6.1
• Version: main

[awni]

Fixed in #2731