Is there any way to allow a task user to make a decision right from their email inbox when they receive the email regarding the task?
The feature is called Direct Approval. You can read about how to configure it here.
I am looking for a way to make a decision from their email client inbox (IE: Gmail or Outlook) using the email body that can be configured as a notification. Like a way to add the actions as buttons in the email HTML.
I'm not sure how it works in Cloud, but for self-hosted you are able to approve it from an email client inbox.
Approve directly from email is supported for Cloud as well, if the user task has been configured with Direct approval enabled as well as Email users enabled, in the received email, there will be link for the approve/reject actions(it is link for Cloud not buttons as self-hosted Forms).