import: add :account_id to the import string for cloudflare_workers_kv_namespace

Fixes #667

Author: jacobbednarz

internal/app/cf-terraforming/cmd/import.go

@@ -45,7 +45,7 @@ var resourceImportStringFormats = map[string]string{
 	"cloudflare_waf_override":          ":zone_id/:id",
 	"cloudflare_waiting_room":          ":zone_id/:id",
 	"cloudflare_worker_route":          ":zone_id/:id",
-	"cloudflare_workers_kv_namespace":  ":id",
+	"cloudflare_workers_kv_namespace":  ":account_id/:id",
 	"cloudflare_zone_lockdown":         ":zone_id/:id",
 	"cloudflare_zone":                  ":id",
 }