Fix server crashes with MUI2

[ALongStringOfNumbers]

What

Fixes crashes when loading the server (via runServer)

However, none of the MUI2 GUIs currently are displaying. Checking Input Bus, Crate, and Hatch

Outcome

Fix server crashes

[ghzdude]

okay, i've determined why ModularPanel's class cannot be found on the server.

our mixin into ModularPanel creates this code:

    @OverrideOnly
    public boolean onMousePressed(int mouseButton) {
        return this.doSafeBool(this::lambda$onMousePressed$3);
    }

    @Overwrite
    @MixinMerged(
        mixin = "gregtech.mixins.mui2.ModularPanelMixin",
        priority = 1000,
        sessionId = "2992ad59-654b-4216-a0d1-f2e33b7582d4"
    )
    private boolean lambda$onMousePressed$3(int mouseButton) {
        // ...
    }

which works fine for the client side, but NOT for the server side for some reason

I suspect the lambda overwrite is to blame, but it's been reworked in #2730 so it should already be fixed there

[ALongStringOfNumbers]

superseded by #2730