Remove PalletInfo impl for ()

[ascjones]

Fixes #7949

polkadot companion: paritytech/polkadot#2409

[gui1117]

To fix this breaking change user must:

• either make use of construct_runtime which declares the ready to use type PalletInfo with correct implementation.
• or implement it themself.

To make use of construct_runtime is test of pallet, one can look at node-template:

substrate/bin/node-template/pallets/template/src/mock.rs

Line 1 in 273bc7b

use crate as pallet_template;

substrate/bin/node-template/pallets/template/src/mock.rs

Lines 9 to 22 in 273bc7b

	type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
	type Block = frame_system::mocking::MockBlock<Test>;
	// Configure a mock runtime to test the pallet.
	frame_support::construct_runtime!(
	pub enum Test where
	Block = Block,
	NodeBlock = Block,
	UncheckedExtrinsic = UncheckedExtrinsic,
	{
	System: frame_system::{Module, Call, Config, Storage, Event<T>},
	TemplateModule: pallet_template::{Module, Call, Storage, Event<T>},
	}
	);

[ascjones]

bot merge

[ghost]

Trying merge.