Fix registry loading when custom registries present

[rfresh2]

Resolves mod compat issues including #4526

Should be forward merged up through 1.21 as same issue is present there

[ZacSharp]

Do you perhaps know how to port this to 1.21.3/1.21.4?
Though it seems like pack loading is broken on 1.21 (EDIT: meant 1.21.3/4) anyway (tested 1.21.3 with tweaker:runClient, 1.21.3 with fabric:runClient, 1.21.4 with tweaker:runClient, 1.21.4 with neoforge 21.4.10-beta)

[rfresh2]

@ZacSharp

1.21(.1): https://github.com/rfresh2/baritone/tree/1.21.1-loottable
1.21.3: https://github.com/rfresh2/baritone/tree/1.21.3-loottable
1.21.4: https://github.com/rfresh2/baritone/tree/1.21.4-loottable (same as 1.21.3)

[rfresh2]

you can cherry pick and throw in your merge PR's to 1.21.1 + 1.21.3

and then i can rebase 1.21.4 pr on top

[rfresh2]

and then i can rebase 1.21.4 pr on top

nvm leijurv merged 1.21.4 already