fix(model-profiles): use posix-compatible substitution in makefile (#35957)

The `refresh_model_profiles` CI workflow has been failing daily since
the `refresh-profiles` Makefile target was added. `make` runs recipes
with `/bin/sh`, which is dash on Ubuntu CI runners — and
`${var//pattern/replacement}` is a bash-only construct that dash rejects
with `Bad substitution`.

## Changes
- Replace bash-ism `$${partner//-/_}` with POSIX-compatible `$$(echo
"$${partner}" | tr '-' '_')` in the `refresh-profiles` target's
`data_dir` construction