Unordered proxy names in API products prevent having empty terraform plan

[zkauker]

Hi,

When you query resources from Apigee API the string list properties are not returned in the same order you specify them during creation. If we don't take this into consideration in the resource read operation it might happen that our terraform plan will never be empty.

I'm going to send a PR for this in a few minutes - this should be handled on the same way it happens now with the company resource's api_products attribute.

Terraform Version

Terraform v0.12.13

Affected Resource(s)

apigee_product

Terraform Configuration Files

resource "apigee_product" "foo_product" {
   ...
   api_resources = ["/**", "/dummy-resource"]
   proxies = ["${apigee_api_proxy.tf_helloworld.name}", "${apigee_api_proxy.tf_helloworld_2.name}", "${apigee_api_proxy.tf_helloworld_3.name}"]
   scopes = ["READ", "WRITE"]
   environments = ["test", "prod"]
   ...
}

Expected Behavior

Don't detect change if the elements of these lists are the same and only the order differs.

Actual Behavior

When the order of these elements differ from the order specified during creation a change is detected by terraform on the resource, so the plan can never be empty.

Steps to Reproduce

1. Create an apigee_product with multiple proxies
2. terraform apply
3. terraform plan
4. The plan should be empty, but it is not.