Add a check to stringSplit that gives a nicer error message is a non-string is passed.

packages/server/src/automations/automationUtils.ts

@@ -131,6 +131,9 @@ export function stringSplit(value: string | string[]) {
   if (value == null || Array.isArray(value)) {
     return value || []
   }
+  if (typeof value !== "string") {
+    throw new Error(`Unable to split value of type ${typeof value}: ${value}`)
+  }
   if (value.split("\n").length > 1) {
     value = value.split("\n")
   } else {