fix(ci): add pytest-rerunfailures to integration test dependencies

The @pytest.mark.flaky(reruns=2) decorator in integration tests requires
pytest-rerunfailures to be installed. Without it, flaky tests silently
skip retries and pytest emits unknown mark warnings.

Author: jariy17

.github/workflows/integration-testing.yml

@@ -161,7 +161,7 @@ jobs:
       - name: Install dependencies
         run: |
           pip install -e .
-          pip install --no-cache-dir pytest pytest-xdist pytest-order requests strands-agents uvicorn httpx starlette websockets ${{ matrix.extra-deps }}
+          pip install --no-cache-dir pytest pytest-xdist pytest-order pytest-rerunfailures requests strands-agents uvicorn httpx starlette websockets ${{ matrix.extra-deps }}
 
       - name: Run integration tests
         env: