ci: remove Python 3.15 from ALL_PYTHON in noxfile

Dependencies (including pyproj and pyarrow) do not yet support Python 3.15, causing prerelease and unit test installation failures in Kokoro. Removes 3.15 from ALL_PYTHON to unblock presubmit builds.

Change-Id: Ice281a12db448a01bc621bc14a5447873773ebb2

Author: shuoweil

noxfile.py

@@ -60,7 +60,7 @@
 
 DEFAULT_PYTHON_VERSION = "3.14"
 
-ALL_PYTHON = ["3.10", "3.11", "3.12", "3.13", "3.14", "3.15"]
+ALL_PYTHON = ["3.10", "3.11", "3.12", "3.13", "3.14"]
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     PYTEST_VERSION,
@@ -283,10 +283,6 @@ def run_unit(session, install_test_extra):
 @nox.session(python=ALL_PYTHON)
 @nox.parametrize("test_extra", [True, False])
 def unit(session, test_extra):
-    if session.python == "3.15":
-        session.skip(
-            "Skipping 3.15 until wheels are available for pyarrow. Also pyproj wheels are needed for dependency geopandas."
-        )
     if test_extra:
         run_unit(session, install_test_extra=test_extra)
     else: