/storage-buckets - s3 - stsAssumeRoleArn not labeled under option 1

under config on the appliance doing a GET, stsAssumeRole can be observed under config key properties, and also sent via POST.

This is missing from the API Documentation.

Confirmed via error message returned on POST that it is parsed and attempted to be utilized


`{
"storageBucket": {
"name": "bob",
"providerType": "s3",
"bucketName": "test-bucket-name",
"config": {
"accessKey": "REDACTED",
"secretKey": "REDACTED",
"stsAssumeRole": "arn:aws:iam::REDACTED_ACCOUNT_NUMBER:role/REDACTED_ROLE_NAME"
},
"retentionPolicyDays": 365,
"retentionPolicyType": "none", // none|delete|backup
"defaultBackupTarget": true,
"createBucket": false,
"copyToStore": false,
"defaultDeploymentTarget": false,
"defaultVirtualImageTarget": false
}
}`