ci : don't specify python version in server-sanitize for broader runner compatibility (#26840)

* don't specify python version for broader runner compatibilty

* run the workflow

.github/workflows/server-sanitize.yml

@@ -25,6 +25,12 @@ on:
       'tools/server/**.*'
     ]
 
+  pull_request:
+    types: [opened, synchronize, reopened]
+    paths: [
+      '.github/workflows/server-sanitize.yml'
+    ]
+
 env:
   LLAMA_ARG_LOG_COLORS: 1
   LLAMA_ARG_LOG_PREFIX: 1
@@ -90,15 +96,18 @@ jobs:
 
       - name: Python setup
         id: setup_python
-        uses: actions/setup-python@v6
-        with:
-          python-version: '3.11'
-          pip-install: -r tools/server/tests/requirements.txt
+        uses: actions/setup-python@v7
+
+      - name: Install Python dependencies
+        run: |
+          python3 -m venv .venv
+          .venv/bin/pip install -r tools/server/tests/requirements.txt
 
       - name: Tests
         id: server_integration_tests
         if: ${{ (!matrix.disabled_on_pr || !github.event.pull_request) }}
         run: |
+          source .venv/bin/activate
           cd tools/server/tests
           export ${{ matrix.extra_args }}
           pytest -v -x -m "not slow"
@@ -107,6 +116,7 @@ jobs:
         id: server_integration_tests_slow
         if: ${{ (github.event.schedule || github.event.inputs.slow_tests == 'true') && matrix.build_type == 'Release' }}
         run: |
+          source .venv/bin/activate
           cd tools/server/tests
           export ${{ matrix.extra_args }}
           SLOW_TESTS=1 pytest -v -x