Do not pollute record changes when loading attributes for the first time

This is done as in rails >= 5.2 the lock! & with_lock methods now
require that the record doesn't have any changes otherwise they'll raise
an error.

Apparently clear_attribute_changes receives an array of attributes which
it should clear.

https://apidock.com/rails/v5.2.3/ActiveModel/Dirty/clear_attribute_changes

lib/vault/latest/encrypted_model.rb

@@ -329,7 +329,7 @@ def __vault_load_attribute!(attribute, options)
           __vault_loaded_attributes << attribute
 
           # Write the virtual attribute with the plaintext value
-          write_attribute(attribute, plaintext)
+          write_attribute(attribute, plaintext).tap { clear_attribute_changes([attribute]) }
         end
 
         # Encrypt all the attributes using Vault and set the encrypted values back