TestData: Do not mutate query in applyTemplateVariables (#87680)

public/app/plugins/datasource/grafana-testdata-datasource/datasource.ts

@@ -142,23 +142,25 @@ export class TestDataDataSource extends DataSourceWithBackend<TestDataDataQuery>
   }
 
   resolveTemplateVariables(query: TestDataDataQuery, scopedVars: ScopedVars) {
-    if (query.labels) {
-      query.labels = this.templateSrv.replace(query.labels, scopedVars);
+    const result = { ...query };
+
+    if (result.labels) {
+      result.labels = this.templateSrv.replace(result.labels, scopedVars);
     }
-    if (query.alias) {
-      query.alias = this.templateSrv.replace(query.alias, scopedVars);
+    if (result.alias) {
+      result.alias = this.templateSrv.replace(result.alias, scopedVars);
     }
-    if (query.scenarioId) {
-      query.scenarioId = this.templateSrv.replace(query.scenarioId, scopedVars) as TestDataQueryType;
+    if (result.scenarioId) {
+      result.scenarioId = this.templateSrv.replace(result.scenarioId, scopedVars) as TestDataQueryType;
     }
-    if (query.stringInput) {
-      query.stringInput = this.templateSrv.replace(query.stringInput, scopedVars);
+    if (result.stringInput) {
+      result.stringInput = this.templateSrv.replace(result.stringInput, scopedVars);
     }
-    if (query.csvContent) {
-      query.csvContent = this.templateSrv.replace(query.csvContent, scopedVars);
+    if (result.csvContent) {
+      result.csvContent = this.templateSrv.replace(result.csvContent, scopedVars);
     }
-    if (query.rawFrameContent) {
-      query.rawFrameContent = this.templateSrv.replace(query.rawFrameContent, scopedVars);
+    if (result.rawFrameContent) {
+      result.rawFrameContent = this.templateSrv.replace(result.rawFrameContent, scopedVars);
     }
   }