I believe you cannot stop the log backups in Azure Backup because this is controlled and managed within SAP HANA itself, you'll need to stop the log backups within SAP HANA.
As you can see when configuring backup for SAP HANA, you'll notice the following:
"In Log Backup, select Enable. This cannot be disabled as SAP HANA manages all log backups."
Step 8 under "Create a backup policy":