[test infra] Bump Python Windows distribtest timeout part 2 (#34685)

Since we added support for Python 3.12, our tests have been taking
longer to complete and we've been seeing an increase in timeout errors.

We already increased timeout in #34550, this PR increase timeout for
release and pull_request jobs.

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tools/internal_ci/windows/pull_request/grpc_distribtests_python.cfg

@@ -16,7 +16,7 @@
 
 # Location of the continuous shell script in repository.
 build_file: "grpc/tools/internal_ci/windows/grpc_distribtests_python.bat"
-timeout_mins: 120
+timeout_mins: 240
 action {
   define_artifacts {
     regex: "**/*sponge_log.*"

tools/internal_ci/windows/release/grpc_distribtests_python.cfg

@@ -16,7 +16,7 @@
 
 # Location of the continuous shell script in repository.
 build_file: "grpc/tools/internal_ci/windows/grpc_distribtests_python.bat"
-timeout_mins: 120
+timeout_mins: 240
 action {
   define_artifacts {
     regex: "**/*sponge_log.*"