There are no controls built into Windows to control this as these are third party services and thus there's nothing in Intune either (as Intune is simply a policy engine for the various managed platforms and doesn't add capabilities to the underlying platform).
Having said that, there are steps you can take including the following (there may be others as well):
- Block the traffic at a network level using a firewall or proxy
- Block the installation of the clients using AppLocker or WDAC
- Use Defender for Cloud Apps: https://learn.microsoft.com/en-us/defender-cloud-apps/protect-dropbox