Alerting: Fix threshold params (#111645)

* fix threshold params

* update tests

public/app/features/expressions/components/__snapshots__/hysteresis.test.ts.snap

@@ -72,7 +72,6 @@ exports[`thresholdReducer should update Threshold Type, and unloadEvaluator para
     {
       "evaluator": {
         "params": [
-          10,
           0,
         ],
         "type": "lt",
@@ -90,7 +89,6 @@ exports[`thresholdReducer should update Threshold Type, and unloadEvaluator para
       "type": "query",
       "unloadEvaluator": {
         "params": [
-          10,
           0,
         ],
         "type": "gt",

public/app/features/expressions/components/hysteresis.test.ts

@@ -159,7 +159,7 @@ describe('thresholdReducer', () => {
     expect(newState.conditions[0].evaluator.type).toEqual(EvalFunction.IsBelow);
     expect(newState.conditions[0].unloadEvaluator?.type).toEqual(EvalFunction.IsAbove);
     expect(onError).toHaveBeenCalledWith(undefined);
-    expect(newState.conditions[0].unloadEvaluator?.params[0]).toEqual(10);
+    expect(newState.conditions[0].unloadEvaluator?.params[0]).toEqual(0);
   });
   it('Should update unlooadEvaluator when checking hysteresis', () => {
     const initialState: ThresholdExpressionQuery = {

public/app/features/expressions/components/thresholdReducer.ts

@@ -33,6 +33,9 @@ export const thresholdReducer = createReducer<ThresholdExpressionQuery>(
       //set new type in evaluator
       state.conditions[0].evaluator.type = typeInPayload;
 
+      //reset params
+      state.conditions[0].evaluator.params = [0];
+
       // check if hysteresis is checked
       const hsyteresisIsChecked = Boolean(state.conditions[0].unloadEvaluator);