Move title fieldnames to Identity constants

src/services/autofillConstants.ts

@@ -190,6 +190,8 @@ export class IdentityAutoFillConstants {
     "data-recurly",
   ];
 
+  static readonly TitleFieldNames: string[] = ["honorific-prefix", "prefix", "title"];
+
   static readonly FirstnameFieldNames: string[] = [
     // English
     "f-name",