fix(quickadapter): preserve rsm parameter for CatBoost GPU pairwise modes (#37)

fix(quickadapter): preserve rsm parameter for CatBoost GPU pairwise modes (#37)

* fix(quickadapter): preserve rsm parameter for CatBoost GPU pairwise modes

The previous fix unconditionally removed the rsm parameter when using GPU,
but according to CatBoost documentation, rsm IS supported on GPU for
pairwise loss functions (PairLogit and PairLogitPairwise).

This commit refines the logic to only remove rsm for non-pairwise modes
on GPU, allowing users to benefit from rsm optimization when using
pairwise ranking loss functions.

Reference: https://github.com/catboost/catboost/issues/983

* refactor: rename constant and remove comments

* refactor(quickadapter): define _CATBOOST_GPU_RSM_LOSS_FUNCTIONS as global constant

- Define _CATBOOST_GPU_RSM_LOSS_FUNCTIONS as a reusable global constant
- Remove duplicate definitions in fit_regressor() and get_optuna_study_model_parameters()
- Improves maintainability: single source of truth for GPU rsm compatibility
- Ensures consistency between runtime logic and Optuna hyperparameter search

* chore: bump version to 3.10.8

Includes:
- CatBoost GPU rsm parameter fix for pairwise loss functions
- Optuna hyperparameter search optimization for rsm parameter
- Global constant for GPU rsm compatibility