ibm_resource_instance data source should not need resource group id

[srikar-git]

I can get service-instance details of a cos instance like

ic resource service-instance COSForAgentLogging

But in terraform I can't do

data "ibm_resource_instance" "cos_instance" {
  name    = var.cos_instance_name
  service = "cloud-object-storage"
}

Note: I didn't target any region or resource group.

Moreover, the datasource page says only 'name' as required parameter

[srikar-git]

Tested with 1.48.0 Provider version and it works. Thank You.