ci: Separate Rust setup job to avoid redundant installations

Ticket: BTC-0
Co-authored-by: aider <[email protected]>

Author: OttoAllmendinger

.github/workflows/ci.yml

@@ -12,14 +12,8 @@ on:
   workflow_dispatch:
 
 jobs:
-  unit-test:
+  setup-rust:
     runs-on: ubuntu-latest
-
-    strategy:
-      fail-fast: false
-      matrix:
-        node-version: [18.x, 20.x]
-
     steps:
       - uses: actions/checkout@v4
         with:
@@ -36,6 +30,19 @@ jobs:
           cargo install wasm-pack --version 0.13.1
           cargo install wasm-opt --version 0.116.1
 
+  unit-test:
+    needs: setup-rust
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version: [18.x, 20.x]
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
+
       - name: Setup node ${{ matrix.node-version }}
         uses: actions/setup-node@v3
         with: