Only set the attribute value in reify when it's different

[tubaxenor]

• Wrote good commit messages.
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new
  code introduces user-observable changes.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.

This is related to https://github.com/paper-trail-gem/paper_trail/pull/1468/files#r1601766553

We shouldn't set something again if the value is no difference from the original value. In some cases such like read only attributes might already set with a default value and will not change over time, this is helpful and will not violate Rails 7.1's new default config raise_on_assign_to_attr_readonly.

[jaredbeck]

Looks good, please add an entry to the Changlog under "Fixed"

[jaredbeck]

@ngan @professor @technicalpickles Thoughts?

[ngan]

Yeah, I think this is a reasonable approach. @tubaxenor can make the request changeling updates when he's back online.