Relax account display name length limit (#39458)

app/models/account.rb

@@ -76,7 +76,7 @@ class Account < ApplicationRecord
   URL_PREFIX_RE = %r{\Ahttp(s?)://[^/]+}
   USERNAME_ONLY_RE = /\A#{USERNAME_RE}\z/i
   USERNAME_LENGTH_LIMIT = 30
-  DISPLAY_NAME_LENGTH_LIMIT = 30
+  DISPLAY_NAME_LENGTH_LIMIT = 40
   NOTE_LENGTH_LIMIT = 500
 
   # Hard limits for federated content