ci: workaround contract test failure (#1086)

- **ci(node-server-sdk): put in contract test workaround**
- **ci: workaround contract test breakage**

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Low risk: CI-only change that pins an external test harness commit;
main risk is future brittleness if the pinned SHA becomes incompatible
or is removed.
> 
> **Overview**
> Pins the `sdk-test-harness` used by the server-node CI contract tests
to a specific commit SHA instead of checking out `feat/fdv2`, with
inline comments noting this as a temporary workaround for upstream
harness changes (SDK-1798). This stabilizes contract test runs until the
SDK supports the newer harness requirements.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
829383e. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: joker23

.github/workflows/server-node.yml

@@ -38,12 +38,16 @@ jobs:
       - name: Launch the test service in the background
         run: yarn contract-test-service 2>&1 &
       - name: Clone and run contract tests from feat/fdv2 branch
+        # NOTE: This is a temporary workaround to run the contract tests from the feat/fdv2 branch.
+        # The commit hash is a few commits before the HEAD of the feat/fdv2 branch. We do this because
+        # the HEAD of the feat/fdv2 branch requires the synchronizers be passed as a list which is not
+        # implemented yet. (SDK-1798)
         run: |
           mkdir -p /tmp/sdk-test-harness
           git clone https://github.com/launchdarkly/sdk-test-harness.git /tmp/sdk-test-harness
           cp ./contract-tests/testharness-suppressions-fdv2.txt /tmp/sdk-test-harness/testharness-suppressions-fdv2.txt
           cd /tmp/sdk-test-harness
-          git checkout feat/fdv2
+          git checkout de833af990da23a89b66c5366809b5be8c27e3f8
           go build -o test-harness .
           ./test-harness -url http://localhost:8000 -debug --skip-from=testharness-suppressions-fdv2.txt
         env: