### What this PR does / why we need it?
Migrate the torch profiler configuration from deprecated environment
variables (`VLLM_TORCH_PROFILER_DIR`, `VLLM_TORCH_PROFILER_WITH_STACK`,
`VLLM_TORCH_PROFILER_WITH_PROFILE_MEMORY`) to the explicit
`ProfilerConfig` object, aligning with vLLM's configuration best
practices.
The profiler environment variable approach is deprecated in vLLM and
will be removed in v0.14.0 or v1.0.0.
### Does this PR introduce _any_ user-facing change?
yes, for deverlopers who want to fetch profiler, he should use `--profiler-config` instead of `VLLM_TORCH_PROFILER_DIR`
### How was this patch tested?
- vLLM version: v0.13.0
- vLLM main:
11b6af5280
Signed-off-by: Meihan-chen <jcccx.cmh@gmail.com>
9cad1a8349