CI: add test case when graphic is enabled but server mode is disabled

Author: w0lek

.github/workflows/test.yml

@@ -197,6 +197,11 @@ jobs:
             params: '-DVTR_ASSERT_LEVEL=3 -DWITH_BLIFEXPLORER=on -DVPR_USE_EZGL=off',
             suite: 'vtr_reg_basic'
           },
+          {
+            name: 'Basic with NO_SERVER',
+            params: '-DVTR_ASSERT_LEVEL=3 -DWITH_BLIFEXPLORER=on -DVPR_USE_EZGL=on -DVPR_USE_SERVER=off',
+            suite: 'vtr_reg_basic'
+          },
           {
             name: 'Basic with CAPNPROTO disabled',
             params: '-DVTR_ASSERT_LEVEL=3 -DWITH_BLIFEXPLORER=on -DVTR_ENABLE_CAPNPROTO=off',