Provide more help understanding what triggers "Non-translatable fields can only be changed when updating the current revision"

Problem/Motivation

These type of warnings seem to come up now and again and people end up at issues like 🐛 Non-translatable fields can only be changed when updating the current revision. Needs work even without using entity_reference_revisions (e.g. using layout builder). The warning is hard to narrow down where the underlying problem is.

Steps to reproduce

1. Get to this error via some means
2. Try to understand what entity/nested entity/field causes the issue

Proposed resolution

Decide on some mechanism to provide more developer friendly details in ContentEntityBase::hasTranslationChanges() probably where we loop through the fields.

1. Can we add something to the logs perhaps?
2. Or can we even have the message specifically say which fields cause the issue since we have access to the field definitions?
3. Or perhaps an event that a contrib module can subscribe to to help debug

Remaining tasks

1. Decide on approach
2. Implement

User interface changes

TBD

Introduced terminology

N/A

API changes

N/A

Data model changes

N/A

Release notes snippet

TBD