tests(firestore-send-email): refactor tests

Author: HassanBahati

firestore-send-email/functions/src/validation.ts

@@ -185,12 +185,8 @@ function formatZodError(
     const path = issue.path.length > 0 ? issue.path.join(".") : context;
     switch (issue.code) {
       case "invalid_type":
-        if (issue.message && !issue.message.startsWith("Expected")) {
-          const customMessage = issue.message.replace(
-            /Field 'attachments'/g,
-            `Field '${path}'`
-          );
-          return customMessage;
+        if (issue.received === "undefined") {
+          return `Field '${path}' must be a ${issue.expected}`;
         }
 
         if (issue.expected === "string") {