strip_tags(): Passing null to parameter #1 ($string) of type string is deprecated

Problem/Motivation

After updating from php 5.6 to php8.1 I am getting this warning
strip_tags(): Passing null to parameter #1 ($string) of type string is deprecated in views_timelinejs_plugin_style_timelinejs->build_date() (line 474 of .../modules/contrib/views_timelinejs/views_timelinejs_plugin_style_timelinejs.inc).

Steps to reproduce

I am not sure why it is sending an empty field to this function but when it does the warning appears/

Proposed resolution

Wrapping the try/catch in an if statement fixes the issue.