Validate json and don't allow null parameter values when running workflow (#866)

skyvern-frontend/src/routes/workflows/RunWorkflowForm.tsx

@@ -1,5 +1,4 @@
 import { getClient } from "@/api/AxiosClient";
-import { WorkflowParameter } from "@/api/types";
 import { Form, FormControl, FormField, FormItem } from "@/components/ui/form";
 import { useCredentialGetter } from "@/hooks/useCredentialGetter";
 import { useMutation, useQueryClient } from "@tanstack/react-query";
@@ -22,6 +21,7 @@ import fetchToCurl from "fetch-to-curl";
 import { apiBaseUrl } from "@/util/env";
 import { useApiCredential } from "@/hooks/useApiCredential";
 import { copyText } from "@/util/copyText";
+import { WorkflowParameter } from "./types/workflowTypes";
 
 type Props = {
   workflowParameters: Array<WorkflowParameter>;
@@ -152,6 +152,9 @@ function RunWorkflowForm({ workflowParameters, initialValues }: Props) {
                             return "Invalid JSON";
                           }
                         }
+                        if (value === null) {
+                          return "This field is required";
+                        }
                       },
                     }}
                     render={({ field }) => {

skyvern-frontend/src/routes/workflows/WorkflowRunParameters.tsx

@@ -1,9 +1,12 @@
 import { getClient } from "@/api/AxiosClient";
-import { WorkflowApiResponse, WorkflowParameterValueType } from "@/api/types";
 import { useCredentialGetter } from "@/hooks/useCredentialGetter";
 import { useQuery } from "@tanstack/react-query";
 import { useLocation, useParams } from "react-router-dom";
 import { RunWorkflowForm } from "./RunWorkflowForm";
+import {
+  WorkflowApiResponse,
+  WorkflowParameterValueType,
+} from "./types/workflowTypes";
 
 function defaultValue(type: WorkflowParameterValueType) {
   switch (type) {