feat: query prompt template support in chatflow (#3791)

Co-authored-by: Joel <iamjoel007@gmail.com>

web/app/components/base/prompt-editor/constants.tsx

@@ -30,6 +30,9 @@ export const checkHasQueryBlock = (text: string) => {
 * {{#1711617514996.sys.query#}} => [sys, query]
 */
 export const getInputVars = (text: string): ValueSelector[] => {
+  if (!text)
+    return []
+
   const allVars = text.match(/{{#([^#]*)#}}/g)
   if (allVars && allVars?.length > 0) {
     // {{#context#}}, {{#query#}} is not input vars