Make go vet pass

The rpcclient constructor could not see the centralized
Encoding flag because it didn't have the necessary build
constraints. Added the constraints in lib_test.go files
where it wasn't alone. In all the other cases, it was
moved to the first file where it was needed.

.github/workflows/integration_tests.yaml

@@ -48,11 +48,12 @@ jobs:
         run: |
           ansible-playbook data/ansible/integration_tests/main.yaml -i localhost, -c local -e "ansible_user=$(whoami) cgrates_dir=$GITHUB_WORKSPACE clone_repository=false install_go=false"
 
-      - name: Run integration tests
-        run: |
-          sudo env "PATH=$PATH" ./integration_test.sh
-
       - name: Run flaky tests
         continue-on-error: true 
         run: |
           sudo env "PATH=$PATH" ./flaky_test.sh
+          
+      - name: Run integration tests
+        run: |
+          sudo env "PATH=$PATH" ./integration_test.sh
+