Added lint warning for gform_post_render hooks on AJAX enabled forms.

[veryspry]

Context

Slack: https://gravitywiz.slack.com/archives/C04PLMYN38W/p1736521082881049

Pertinent information:

we had a report of an issue with gform/postRender, the code was running an increasing number of times with each next,
previous, validation error redisplay that occurred

code chest is registering the snippets as form init scripts which adds them via gform_post_render, so each time that fires > it adds the listeners for the events from the code snippets again

Summary

Using gform_post_render, gform/postRender or gform/post_render on AJAX enabled forms can be problematic as the hook callbacks can be registered multiple times. (See above details)

This adds a lint warning to the JavaScript editor when these strings are detected.

[claygriffiths]

Nice work! Looks like this was tough to navigate.