`PhosphophylliteFluidStack` `getFluid` problem

[Technici4n]

We discussed this on FC, the gist is:

• amount != 0
• Forge's internal isEmpty is true even though the stack is not empty

• public final Fluid getFluid()
  {
      return isEmpty ? Fluids.EMPTY : fluidDelegate.get();
  }

Then the following (AE2) code crashes because the returned fluid is Fluids.EMPTY:

FluidStack fluidStack = fluidHandler.getStackInSlot(...);
if (fluidStack.isEmpty()) {
    return null;
}
var newStack = new FluidStack(fluidStack.getFluid(), 1);
newStack.setTag(fluidStack.getTag()); // Crashes: can't modify empty