If it were me doing this, I would probably use CLASP and clone all the scripts to my local machine. Then I would use VSCode to do the searching. However, that doesn't answer your question.
You could first go to the Advanced Drive API
reference page to list all your files. On the right side is the "Try this method" sidebar. After some trial and error, I ended up with this query:
Input boxes (leave all empty except these):
q - mimeType = "application/vnd.google-apps.script"
click on "Show standard parameters" and enter:
fields - items(id,title)
(or use this
handy url - it may fill it all in for you) then press Execute and give permission to run under your account.
If all went well, in the lower right should be a Green box with JSON output of all your script files (scriptname and ID).
From there, you should be able to iterate over each scriptID, get the file, search for your desired parameter, and if found log that scriptID as a positive match.
If nothing else, that gets you on your way.