chore: Remove pin of matplotlib

Author: xmatthias

requirements-freqai.txt

@@ -6,9 +6,6 @@
 scikit-learn==1.6.0
 joblib==1.4.2
 catboost==1.2.7; 'arm' not in platform_machine
-# Pin Matplotlib - it's depended on by catboost
-# Temporary downgrade of matplotlib due to https://github.com/matplotlib/matplotlib/issues/28551
-matplotlib==3.10.0
 lightgbm==4.5.0
 xgboost==2.1.3
 tensorboard==2.18.0