Deneb PR feedback updates (#4716)

* move length update outside of if let in LRU cache

* add comment and use hex for G1_POINT_AT_INFINITY

* remove some misleading comments from `ssz_snappy`

* make sure we can't overflow on blobs by range requests with large counts

* downgrade gossip verification internal availability check error

* change blob rpc responses from BlockingFnWithManualSendOnIdle to BlockingFn

* remove unnecessary collect in blobs by range response

* add a comment to blobs by range response start slot logic

* typo persist_data_availabilty_checker -> persist_data_availability_checker

* unify cheap_state_advance_to_obtain_committees

beacon_node/lighthouse_network/src/rpc/protocol.rs

@@ -574,7 +574,7 @@ impl<TSpec: EthSpec> InboundRequest<TSpec> {
             InboundRequest::Goodbye(_) => 0,
             InboundRequest::BlocksByRange(req) => *req.count(),
             InboundRequest::BlocksByRoot(req) => req.block_roots().len() as u64,
-            InboundRequest::BlobsByRange(req) => req.count * TSpec::max_blobs_per_block() as u64,
+            InboundRequest::BlobsByRange(req) => req.max_blobs_requested::<TSpec>(),
             InboundRequest::BlobsByRoot(req) => req.blob_ids.len() as u64,
             InboundRequest::Ping(_) => 1,
             InboundRequest::MetaData(_) => 1,