Repeaters input to transmitters are ignored

[felix920506]

Bug report

I'm using version: 4.2.1
I'm on Minecraft: 1.21.1
I'm running: Paper

Seen results:
When transmitter signs are powered using transmitters (through a block or directly) the channel isn't powered

Expected results:
The channel should become powered upon transmitter being powered by a repeater

How to reproduce:

1. Create a transmitter sign
2. Point a repeater at it
3. Power the repeater
4. See error

Additional info:
More info you'd like to give us