ci: drop nydus-unit-test-coverage

There is no need to run the nydus unit tests twice, once in
nydus-unit-test-coverage, the other in nydus-unit-test.

Signed-off-by: Peng Tao <bergwolf@hyper.sh>

Author: bergwolf

.github/workflows/smoke.yml

@@ -248,8 +248,15 @@ jobs:
     - name: Unit Test
       run: |
         sudo -E ENABLE_DEBUG=1 "PATH=$PATH" make ut-nextest
+        sudo -E "PATH=$PATH" make generate-codecov
+    - name: Upload nydus coverage file
+      uses: actions/upload-artifact@v6
+      with:
+        name: nydus-test-coverage-artifact
+        path: |
+          coverage/coverage.info
 
-  contrib-unit-test-coverage:
+  contrib-unit-test:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
@@ -269,36 +276,9 @@ jobs:
         path: |
           contrib/nydusify/coverage.txt
 
-  nydus-unit-test-coverage:
-    runs-on: ubuntu-latest
-    env:
-      CARGO_TERM_COLOR: always
-    steps:
-      - uses: actions/checkout@v6
-      - name: Rust Cache
-        uses: Swatinem/rust-cache@v2
-        with:
-          cache-on-failure: true
-          shared-key: Linux-cargo-amd64
-          save-if: ${{ github.ref == 'refs/heads/master' }}
-      - name: Install cargo-llvm-cov
-        uses: taiki-e/install-action@cargo-llvm-cov
-      - name: Fscache Setup
-        run: sudo bash misc/fscache/setup.sh
-      - name: Generate code coverage
-        run: |
-          sudo -E ENABLE_DEBUG=1 "PATH=$PATH" make ut
-          sudo -E "PATH=$PATH" make generate-codecov
-      - name: Upload nydus coverage file
-        uses: actions/upload-artifact@v6
-        with:
-          name: nydus-test-coverage-artifact
-          path: |
-            coverage/coverage.info
-
   upload-coverage-to-codecov:
     runs-on: ubuntu-latest
-    needs: [contrib-unit-test-coverage, nydus-unit-test-coverage]
+    needs: [contrib-unit-test, nydus-unit-test]
     steps:
     - uses: actions/checkout@v6
     - name: Download nydus coverage file