Hello Shalom,
I don't know if we have a feature like that built into Genesys Cloud. While I haven't tried it myself, I wonder if you could have the message go through an Inbound Message flow and check if there are any non messages or check if the message only contains text and then either strip out the anything that is not text or block the message from being delivered.
I would also recommend that if you would like to see something like this integrated into the platform, you should submit your request through the Product Ideas Lab.
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Jason Kleitz
Online Community Manager/Moderator
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