cw scrape job: fix modifyplan when creating a new resource

[tristanburgess]

We implemented ModifyPlan on the AWS CW scrape job resources in #1789. This was done in order to only make disabled_reason computed when the enabled state is being set to false. This function apparently runs even on resource creation, however, so an error was being thrown because the state was nil.

This PR handles the case that the state is nil, again depending on the planned enabled state.

enabled=true

  + resource "grafana_cloud_provider_aws_cloudwatch_scrape_job" "sandbox-ec2" {
      + aws_account_resource_id = (known after apply)
      + enabled                 = true
      + export_tags             = true
      + id                      = (known after apply)
      + name                    = "tf-managed-scrape-job"
      + regions                 = [
          + "us-east-1",
          + "us-east-2",
        ]
      + stack_id                = "1"
        # (1 unchanged attribute hidden)

      + service {
          + name                    = "AWS/EC2"
          + scrape_interval_seconds = 300
          + tags_to_add_to_metrics  = [
              + "eks:cluster-name",
            ]

          + metric {
              + name       = "CPUUtilization"
              + statistics = [
                  + "Average",
                ]
            }
          + metric {
              + name       = "StatusCheckFailed"
              + statistics = [
                  + "Maximum",
                ]
            }
        }
    }

enabled=false

  + resource "grafana_cloud_provider_aws_cloudwatch_scrape_job" "sandbox-ec2" {
      + aws_account_resource_id = (known after apply)
      + disabled_reason         = (known after apply)
      + enabled                 = false
      + export_tags             = true
      + id                      = (known after apply)
      + name                    = "tf-managed-scrape-job"
      + regions                 = [
          + "us-east-1",
          + "us-east-2",
        ]
      + stack_id                = "1"

      + service {
          + name                    = "AWS/EC2"
          + scrape_interval_seconds = 300
          + tags_to_add_to_metrics  = [
              + "eks:cluster-name",
            ]

          + metric {
              + name       = "CPUUtilization"
              + statistics = [
                  + "Average",
                ]
            }
          + metric {
              + name       = "StatusCheckFailed"
              + statistics = [
                  + "Maximum",
                ]
            }
        }
    }

[github-actions]

In order to lower resource usage and have a faster runtime, PRs will not run Cloud tests automatically.
To do so, a Grafana Labs employee must trigger the cloud acceptance tests workflow manually.

[thepalbi]

sgtm

[tristanburgess]

also fixed an extra edge case when the provider isn't configured with the right params but you try to create a resource anyways:

│ Error: The Grafana Provider is missing a configuration for the Cloud Provider API.
│
│   with grafana_cloud_provider_aws_account.test,
│   on main.tf line 27, in resource "grafana_cloud_provider_aws_account" "test":
│   27: resource "grafana_cloud_provider_aws_account" "test" {
│
│ Please ensure that cloud_provider_url and cloud_provider_access_token are set in the provider configuration.