Decoding JWT body from webhooks

hey! so another problem has cropped up.
the workflow stops, if first_name does not exist in the decoded JWT data, gives an error like,
ERROR: Cannot read properties of undefined (reading ‘fieldValue’) [Line 13 | Item Index: 0]

How do I prevent this? Wix uses a single webhook trigger for any forms that are filled in the website.

is it possible to incorporate an if-else statement at the end, after return? execute finding the fields if the data is from a particular form only?