Remove superflous parameter overseer_enable_anyways and make parachain node type more explicit (#7617)

* Remove superflous parameter `overseer_enable_anyways`

We don't need this flag, as we don't need the overseer enabled when the
node isn't a collator or validator.

* Rename `IsCollator` to `IsParachainNode`

`IsParachainNode` is more expressive and also encapsulates the state of
the parachain node being a full node. Some functionality like the
overseer needs to run always when the node runs alongside a parachain
node. The parachain node needs the overseer to e.g. recover PoVs. Other
things like candidate validation or pvf checking are only required for
when the node is running as validator.

* FMT

* Fix CI

polkadot/node/network/approval-distribution/src/lib.rs

@@ -1319,13 +1319,13 @@ impl State {
 			}
 
 			// Here we're leaning on a few behaviors of assignment propagation:
-			//   1. At this point, the only peer we're aware of which has the approval
-			//      message is the source peer.
-			//   2. We have sent the assignment message to every peer in the required routing
-			//      which is aware of this block _unless_ the peer we originally received the
-			//      assignment from was part of the required routing. In that case, we've sent
-			//      the assignment to all aware peers in the required routing _except_ the original
-			//      source of the assignment. Hence the `in_topology_check`.
+			//   1. At this point, the only peer we're aware of which has the approval message is
+			//      the source peer.
+			//   2. We have sent the assignment message to every peer in the required routing which
+			//      is aware of this block _unless_ the peer we originally received the assignment
+			//      from was part of the required routing. In that case, we've sent the assignment
+			//      to all aware peers in the required routing _except_ the original source of the
+			//      assignment. Hence the `in_topology_check`.
 			//   3. Any randomly selected peers have been sent the assignment already.
 			let in_topology = topology
 				.map_or(false, |t| t.local_grid_neighbors().route_to_peer(required_routing, peer));