Ensure submission state is reset on onSubmit error

ui/app/pages/settings/networks-tab/network-form/network-form.component.js

@@ -134,6 +134,7 @@ export default class NetworkForm extends PureComponent {
       isSubmitting: true,
     })
 
+    try {
       const {
         setRpcTarget,
         rpcUrl: propsRpcUrl,
@@ -180,6 +181,12 @@ export default class NetworkForm extends PureComponent {
       if (networksTabIsInAddMode) {
         onClear()
       }
+    } catch (error) {
+      log.error('Unexpected error during form submission.', error)
+      this.setState({
+        isSubmitting: false,
+      })
+    }
   }
 
   onCancel = () => {