CI: Add explicite collections contract build to the coverage job

.github/workflows/codecov.yml

@@ -11,8 +11,18 @@ jobs:
       - uses: actions/checkout@v4
       - name: Install Rust
         run: rustup update stable
+      - name: Install stable toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust-version }}
+          target: wasm32-unknown-unknown
+          override: true
       - name: Install cargo-llvm-cov
         uses: taiki-e/install-action@cargo-llvm-cov
+      # Explicitly build the collections contract first
+      - name: Build Collections Contract
+        run: make build
       - name: Generate code coverage
         run: cargo llvm-cov --all-features --workspace --codecov --output-path codecov.json
       - name: Upload coverage to Codecov