collective pallet: sort genesis members and enforce max len constraint (#13988)

* insert members in sorted order

* improve variable name

* enforce genesis members length constraint

substrate/frame/collective/src/lib.rs

@@ -246,6 +246,10 @@ pub mod pallet {
 				self.members.len(),
 				"Members cannot contain duplicate accounts."
 			);
+			assert!(
+				self.members.len() <= T::MaxMembers::get() as usize,
+				"Members length cannot exceed MaxMembers.",
+			);
 
 			Pallet::<T, I>::initialize_members(&self.members)
 		}
@@ -1107,6 +1111,8 @@ impl<T: Config<I>, I: 'static> InitializeMembers<T::AccountId> for Pallet<T, I>
 	fn initialize_members(members: &[T::AccountId]) {
 		if !members.is_empty() {
 			assert!(<Members<T, I>>::get().is_empty(), "Members are already initialized!");
+			let mut members = members.to_vec();
+			members.sort();
 			<Members<T, I>>::put(members);
 		}
 	}