Lift minimum Protobuf version for Python 3.14+ on MacOS (onnx#7419)

### Motivation and Context

We are seeing test errors on MacOS and Python 3.14. These errors come
from Protobuf and they were fixed in
#protocolbuffers/protobuf#15999 and the PR was
contained since 6.31.0.

Signed-off-by: Yuanyuan Chen <cyyever@outlook.com>

Author: cyyever

requirements-min.txt

@@ -1,6 +1,7 @@
 # Minimum package versions that ONNX supports
 # https://endoflife.date/numpy
-protobuf==4.25.1
+protobuf==4.25.1; python_version<"3.14" or sys_platform != "darwin"
+protobuf==6.31.0; python_version>="3.14" and sys_platform == "darwin"
 numpy==1.23.2; python_version=="3.10"
 numpy==1.23.2; python_version=="3.11"
 numpy==1.26.0; python_version=="3.12"

requirements-release_build.txt

@@ -1,4 +1,5 @@
 build
 wheel
-protobuf==4.25.1
+protobuf==4.25.1; python_version<"3.14" or sys_platform != "darwin"
+protobuf==6.31.0; python_version>="3.14" and sys_platform == "darwin"
 setuptools