🐛 declare additional attributes that are multiline string for gcp (#5992)

Author: username-is-already-taken2

providers/os/id/metadata/crawler.go

@@ -93,7 +93,10 @@ var multilineStringFields = []string{
 	// GCP
 	"instance/service-accounts/*/scopes",
 	"instance/attributes/ssh-keys",
+	"instance/attributes/sshKeys",
 	"instance/attributes/startup-script",
+	"instance/attributes/shutdown-script",
+	"instance/attributes/user-data",
 }
 
 // isMultilineString checks if a path should be treated as a raw multiline string.