Fix for esphome 2023.12.x - remaining fix

[madimadi]

What does this implement/fix?

Rename display.DisplayBufferRef was missing in previous PR

Types of changes

• [ x] Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Related issue or feature (if applicable): fixes
https://github.com/ashald/esphome/pull/4/files

Test Environment

• [x ] ESP32
• ESP32 IDF
• ESP8266
• RP2040

Checklist:

• [ x] The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

This is a fix on compile error:

AttributeError: module 'esphome.components.display' has no attribute 'DisplayBufferRef'. Did you mean: 'DisplayBuffer'?