chore: Use the contract test service action. (#456)

Author: kinyoklion

.github/workflows/server-node.yml

@@ -19,9 +19,6 @@ jobs:
         # Node versions to run on.
         version: [18, 21]
 
-    env:
-      TEST_HARNESS_PARAMS: '--skip-from=./contract-tests/testharness-suppressions.txt'
-
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
@@ -34,5 +31,10 @@ jobs:
         with:
           workspace_name: '@launchdarkly/node-server-sdk'
           workspace_path: packages/sdk/server-node
-      - name: Contract Tests
-        run: yarn run contract-tests
+      - name: Launch the test service in the background
+        run: yarn run contract-test-service 2>&1 &
+      - uses: launchdarkly/gh-actions/actions/[email protected]
+        with:
+          test_service_port: 8000
+          token: ${{ secrets.GITHUB_TOKEN }}
+          extra_params: '--skip-from=./contract-tests/testharness-suppressions.txt'