chore: rename variable for clarity (#12159)

diff --git a/superset-frontend/src/components/ErrorMessage/ParameterErrorMessage.tsx b/superset-frontend/src/components/ErrorMessage/ParameterErrorMessage.tsx
index efc94dc..145200d 100644
--- a/superset-frontend/src/components/ErrorMessage/ParameterErrorMessage.tsx
+++ b/superset-frontend/src/components/ErrorMessage/ParameterErrorMessage.tsx
@@ -79,14 +79,14 @@
                 ([undefinedParameter, templateKeys]) => (
                   <li>
                     {tn(
-                      '%(suggestion)s instead of "%(undefined)s?"',
-                      '%(first_suggestions)s or %(last_suggestion)s instead of "%(undefined)s"?',
+                      '%(suggestion)s instead of "%(undefinedParameter)s?"',
+                      '%(firstSuggestions)s or %(lastSuggestion)s instead of "%(undefinedParameter)s"?',
                       templateKeys.length,
                       {
                         suggestion: templateKeys.join(', '),
-                        first_suggestions: templateKeys.slice(0, -1).join(', '),
-                        last_suggestion: templateKeys[templateKeys.length - 1],
-                        undefined: undefinedParameter,
+                        firstSuggestions: templateKeys.slice(0, -1).join(', '),
+                        lastSuggestion: templateKeys[templateKeys.length - 1],
+                        undefinedParameter,
                       },
                     )}
                   </li>
diff --git a/superset/views/core.py b/superset/views/core.py
index c092b0a..2895340 100755
--- a/superset/views/core.py
+++ b/superset/views/core.py
@@ -2521,21 +2521,21 @@
         if is_feature_enabled("ENABLE_TEMPLATE_PROCESSING"):
             # pylint: disable=protected-access
             ast = template_processor._env.parse(rendered_query)
-            undefined = find_undeclared_variables(ast)  # type: ignore
-            if undefined:
+            undefined_parameters = find_undeclared_variables(ast)  # type: ignore
+            if undefined_parameters:
                 query.status = QueryStatus.FAILED
                 session.commit()
                 raise SupersetTemplateParamsErrorException(
                     message=ngettext(
                         "The parameter %(parameters)s in your query is undefined.",
                         "The following parameters in your query are undefined: %(parameters)s.",
-                        len(undefined),
-                        parameters=utils.format_list(undefined),
+                        len(undefined_parameters),
+                        parameters=utils.format_list(undefined_parameters),
                     )
                     + " "
                     + PARAMETER_MISSING_ERR,
                     extra={
-                        "undefined_parameters": list(undefined),
+                        "undefined_parameters": list(undefined_parameters),
                         "template_parameters": template_params,
                     },
                 )