Added support to overwrite serializer methods in schema class

[sliverc]

Description of the Change

This change makes the DJA schema class compatible with the DRF change introduced with encode/django-rest-framework#7424

Checklist

• PR only contains one change (considered splitting up PR)
• unit-test added
• documentation updated
• CHANGELOG.md updated (only for user relevant changes)
• author name in AUTHORS

[n2ygk]

I thought DRF had decided to stop merging schema generator changes in lieu of recommending an external library, drf-spectacular.

[sliverc]

Thanks for merging. This change actually got integrated 2 years ago and I have just recently stumbled upon it. There is a recent change encode/django-rest-framework#7493 which will affect DJA as well, so it seems minor changes are still merged, but nothing major.

[auvipy]

Thanks for merging. This changed actually got integrated 2 years ago and I have just recently stumbled upon it. There is a recent change encode/django-rest-framework#7493 which will affect DJA as well, so it seems minor changes are still merged, but nothing major.

you are right, but crucial changes for thing important in DRF will also be merged. I know this from conversation with Tom Christie. DRF will deprecate core schema, but improve OpenAPI support.