bazel: only test against python3.12 CI

try to use a different version version will led to the bazel test error:

```sh
bazel test -c opt --test_output=errors //ortools/... //examples/...
...
FAIL: //ortools/pdlp/python:pdlp_test (Exit 1) (see /home/runner/.cache/bazel/_bazel_runner/67ceb8c7c63f44f5a932a40cb5180139/execroot/_main/bazel-out/k8-opt/testlogs/ortools/pdlp/python/pdlp_test/test.log)
INFO: From Testing //ortools/pdlp/python:pdlp_test:
==================== Test output for //ortools/pdlp/python:pdlp_test:
Traceback (most recent call last):
  File "/home/runner/.cache/bazel/_bazel_runner/67ceb8c7c63f44f5a932a40cb5180139/sandbox/processwrapper-sandbox/7369/execroot/_main/bazel-out/k8-opt/bin/ortools/pdlp/python/pdlp_test.runfiles/_main/ortools/pdlp/python/pdlp_test.py", line 23, in <module>
    from ortools.pdlp.python import pdlp
ImportError: Python version mismatch: module was compiled for Python 3.12, but the interpreter version is incompatible: 3.11.10 (main, Oct 16 2024, 04:38:48) [Clang 18.1.8 ].
```

.github/workflows/amd64_linux_bazel.yml

@@ -9,10 +9,10 @@ jobs:
     strategy:
       matrix:
         python: [
-          {version: '3.10'},
-          {version: '3.11'},
+          #{version: '3.10'},
+          #{version: '3.11'},
           {version: '3.12'},
-          {version: '3.13'},
+          #{version: '3.13'},
         ]
       fail-fast: false
     name: Linux • Bazel • Python-${{ matrix.python.version }}

.github/workflows/amd64_macos_bazel.yml

@@ -9,10 +9,10 @@ jobs:
     strategy:
       matrix:
         python: [
-          {version: '3.10'},
-          {version: '3.11'},
+          #{version: '3.10'},
+          #{version: '3.11'},
           {version: '3.12'},
-          {version: '3.13'},
+          #{version: '3.13'},
         ]
       fail-fast: false
     name: MacOS • Bazel • Python-${{ matrix.python.version }}

.github/workflows/arm64_macos_bazel.yml

@@ -9,10 +9,10 @@ jobs:
     strategy:
       matrix:
         python: [
-          {version: '3.10'},
-          {version: '3.11'},
+          #{version: '3.10'},
+          #{version: '3.11'},
           {version: '3.12'},
-          {version: '3.13'},
+          #{version: '3.13'},
         ]
       fail-fast: false
     name: MacOS • Bazel • Python-${{ matrix.python.version }}