Make Trial Spawner "Permenantly Active" using trial Keys, use for mob farms

Trial keys are used for getting loot from the trial chambers, but what about mob loot. A trial key could make a spawner "permanently active" to make mob farms. Here are my suggestions for this:

• Once a Trial Key is used on a spawner, it will spawn new mobs once all the previous ones are killed
• Mob spawns follow the same rules as before, but do not need player line of sight
• Mobs are still persistent
• Additional Trail keys increase the challenge level, effectively increasing the number of mobs spawned per "wave"
• The spawners do not drop rewards
• Implement some way of reverting this, but keys are used are not recovered, maybe once a certain number of keys are used it reverts, like noteblocks or repeaters cycling back

This functionality will allow trial chambers to be easy to build mob farms for a variety of mobs, smaller slime farms, a way to farm Wind Charges, and a simple easy renewable source of persistent mobs for minigames.