INTMDB-400: Empty struct to delete backup distribution configuration

[martinstibbe]

Description

Empty struct to delete backup distribution configuration
Need a way to emit empty copySettings array this to PATCH API call to remove distribution configuration

{
  "clusterId":"63a32ba4zzz3dcaa7eaf",
"clusterName":"test-backups",
"copySettings":[]
}

Link to any related issue(s):

Type of change:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Required Checklist:

• I have signed the MongoDB CLA
• I have added tests that prove my fix is effective or that my feature works
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code

Further comments