sat: disable deprecated warnings in cp_model.py

User can reenable them using:

```py
from ortools.sat.python import cp_model
cp_model.enable_warnings = True
```

ortools/sat/python/cp_model.py

@@ -184,7 +184,7 @@ _IndexOrSeries = Union[pd.Index, pd.Series]
 
 
 # Helper functions.
-
+enable_warnings = False
 
 # warnings.deprecated is python3.13+. Not compatible with Open Source (3.10+).
 # pylint: disable=g-bare-generic
@@ -193,6 +193,7 @@ def deprecated(message: str) -> Callable[[Callable], Callable]:
 
     def deprecated_decorator(func) -> Callable:
         def deprecated_func(*args, **kwargs):
+            if enable_warnings:
                 warnings.warn(
                     f"{func.__name__} is a deprecated function. {message}",
                     category=DeprecationWarning,
@@ -210,6 +211,7 @@ def deprecated_method(func, old_name: str) -> Callable:
     """Wrapper that warns about a deprecated method."""
 
     def deprecated_func(*args, **kwargs) -> Any:
+        if enable_warnings:
             warnings.warn(
                 f"{old_name} is a deprecated function. Use {func.__name__} instead.",
                 category=DeprecationWarning,