Remove unused im-online weights (#3373)

A follow-up of #2265. Removes weights no longer needed.

Author: s0me0ne-unkn0wn

polkadot/runtime/rococo/src/weights/mod.rs

@@ -23,7 +23,6 @@ pub mod pallet_bounties;
 pub mod pallet_child_bounties;
 pub mod pallet_conviction_voting;
 pub mod pallet_identity;
-pub mod pallet_im_online;
 pub mod pallet_indices;
 pub mod pallet_message_queue;
 pub mod pallet_multisig;

polkadot/runtime/rococo/src/weights/pallet_im_online.rs

@@ -24,7 +24,6 @@ pub mod pallet_conviction_voting;
 pub mod pallet_election_provider_multi_phase;
 pub mod pallet_fast_unstake;
 pub mod pallet_identity;
-pub mod pallet_im_online;
 pub mod pallet_indices;
 pub mod pallet_message_queue;
 pub mod pallet_multisig;