benchmark_params.pkl: restore max_consumption_dollars=300000.0 in fixed_params.

The pkl key is consumed by `get_benchmark_params` via
`fixed_params.pop("max_consumption_dollars")` (benchmark.py:119) and
threaded into `inject_consumption_dollars_points`. Earlier regenerations
of the pkl dropped this entry, which broke both `tests/test_model_creation.py`
and pylcm's `benchmark-pr` GPU run (the latter installs aca-model from
this same pkl).

Value (300000.0) matches `MAX_CONSUMPTION_DOLLARS` in
`aca-data/src/aca_data/task_environment_constants.py:23`.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: hmgaudecker