HA discovery configuration dropped when value is null

[ghoz]

What happened?

I have customized some home assistant discovery for specific entities to override the default category from diagnostic to regular sensor.
In order to do that I'm overriding the specific entity_category for the entities in my devices.yaml file, and it works:

'0xieeeAddr':
  friendly_name: Smart_plug
  description: chatty Nous A1Z
  [...]
  homeassistant:
    power:
      entity_category: null
    current:
      entity_category: null
    voltage:
      entity_category: null

However, when making any change using the UI, all entity_category: null are removed.

'0xieeeAddr':
  friendly_name: Smart_plug
  description: chatty Nous A1Z
  [...]
  homeassistant:
    power: {}
    current: {}
    voltage: {}

This might be tied to #22674
I haven't tested if it also occurs in the main configuration file under homeassistant key

note: It is kind of hidden as z2m no longer sends the discovery payload if already sent since #22701 , so home assistant won't see the change unless the retained discovery topics are cleared first (#22977).

What did you expect to happen?

I expected that my configuration would keep my settings.

How to reproduce it (minimal and precise)

1. add a custom home assistant entry in a device configuration with a value of null
2. change a setting in the UI
3. see that the config was changed and the entry removed

Zigbee2MQTT version

1.38.0

Adapter firmware version

20230507

Adapter

Sonoff ZBDongle-P

Setup

container on pi3

Debug log

No response