fix: add custom email error message for signup

packages/web/src/locales/en.json

@@ -116,6 +116,7 @@
   "signupForm.passwordFieldLabel": "Password",
   "signupForm.confirmPasswordFieldLabel": "Confirm password",
   "signupForm.submit": "Sign up",
+  "signupForm.validateEmail": "Email must be valid.",
   "signupForm.passwordsMustMatch": "Passwords must match.",
   "signupForm.mandatoryInput": "{inputName} is required.",
   "loginForm.title": "Login",
@@ -136,4 +137,4 @@
   "resetPasswordForm.passwordFieldLabel": "Password",
   "resetPasswordForm.confirmPasswordFieldLabel": "Confirm password",
   "resetPasswordForm.passwordUpdated": "The password has been updated. Now, you can login."
-}
+}