There are no file and folder exclusions in Defender for Cloud. With one exception, it does not scan files. That is Defender for Endpoint/Antivirus. Defender for Cloud is more focused on security posture and risky configurations. There is an AV scan in Defender for Storage on the commercial side. This does not have direct exclusions but there is a workaround described here.
https://learn.microsoft.com/en-us/azure/defender-for-cloud/defender-for-storage-malware-scan
Defender for Endpoint is the Microsoft AV-EDR service. It has custom indicators than can be used allow files and supports traditional folder exclusions by policy. Though MDE does real-time scanning that reduces the need for traditional exclusions. The fewer exceptions you have the better.