[Fix] Remove empty namespace from plugins' builder (#1073)

In principle, the plugin's workchain should validate whether an input namespace is empty or not, but not all developers are doing this. We assume all empty namespaces are not used, which is by default when submitting a builder in the aiida-core. Here, we simply remove the empty namespace.

src/aiidalab_qe/workflows/__init__.py

@@ -221,7 +221,9 @@ def get_builder_from_protocol(
                 plugin_workchain = entry_point["workchain"]
                 if plugin_workchain.spec().has_input("clean_workdir"):
                     plugin_builder.clean_workdir = clean_workdir
-                setattr(builder, name, plugin_builder)
+                # some plugin's logic depend on whether a input exist or not, but not check if it is empty.
+                # here we remove the empty namespace for safety.
+                setattr(builder, name, plugin_builder._inputs(prune=True))
             else:
                 builder.pop(name, None)