fix(ci): pin Go 1.25 compatible staticcheck

Author: m0wer

.github/workflows/test.yaml

@@ -40,7 +40,7 @@ jobs:
       - name: Run staticcheck
         working-directory: neutrino_server
         run: |
-          go install honnef.co/go/tools/cmd/staticcheck@latest
+          go install honnef.co/go/tools/cmd/staticcheck@v0.7.0
           staticcheck ./...
 
       - name: Run tests
@@ -52,7 +52,7 @@ jobs:
         with:
           files: ./neutrino_server/coverage.out
           flags: unittests
-        if: always()
+        if: ${{ always() && hashFiles('neutrino_server/coverage.out') != '' }}
 
   test-docker-build:
     runs-on: ubuntu-latest