Improve variations in create_report (#3924)

* fix variation in create report

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

pyaedt/modules/PostProcessor.py

@@ -1615,7 +1615,13 @@ def create_report(
             ]
         report.expressions = expressions
         report.domain = domain
-        if not variations:
+        if not variations and domain == "Sweep":
+            variations = self._app.available_variations.nominal_w_values_dict
+            if variations:
+                variations["Freq"] = "All"
+            else:
+                variations = {"Freq": ["All"]}
+        elif not variations and domain != "Sweep":
             variations = self._app.available_variations.nominal_w_values_dict
         if primary_sweep_variable:
             report.primary_sweep = primary_sweep_variable