Fixes Issue #29959, Apply w/o init error message

When going from a local backend to Terraform Cloud, if you skip the
`terraform init` and run `terraform apply` this will give the user more
clear instructions.

Author: barrettclark

internal/command/meta_backend.go

@@ -737,7 +737,7 @@ func (m *Meta) determineInitReason(previousBackendType string, currentBackendTyp
 		diags = diags.Append(tfdiags.Sourceless(
 			tfdiags.Error,
 			"Terraform Cloud initialization required: please run \"terraform init\"",
-			fmt.Sprintf(strings.TrimSpace(errBackendInitCloudMigration), initReason),
+			fmt.Sprintf(strings.TrimSpace(errBackendInitCloud), initReason),
 		))
 	default:
 		diags = diags.Append(tfdiags.Sourceless(
@@ -1510,17 +1510,6 @@ hasn't changed and try again. At this point, no changes to your existing
 configuration or state have been made.
 `
 
-const errBackendInitCloudMigration = `
-Reason: %s.
-
-Migrating to Terraform Cloud requires reinitialization, to discover which Terraform Cloud workspaces belong to this configuration and to optionally migrate existing state to the corresponding Terraform Cloud workspaces.
-
-To re-initialize, run:
-  terraform init
-
-Terraform has not yet made changes to your existing configuration or state.
-`
-
 const errBackendInitCloud = `
 Reason: %s.