Fix and improve handling of empty columns after getBlobs response (#9361)

This PR fixes two issues:

1. This condition is inverted: dfb259171a/beacon_node/network/src/network_beacon_processor/gossip_methods.rs (L1507-L1508)
We are supposed to filter out incomplete columns when we DON'T have local blobs yet!
2. When the EL returns no blobs, we never store a partial in the assembler, and this code fails to publish our need to the network, as no partials are returned: dfb259171a/beacon_node/network/src/network_beacon_processor/mod.rs (L1038-L1050)


  The simple fix for 1 would be to invert the condition, but we can improve the flow here: Instead of not publishing anything, we can publish what we got, but not request anything. This ties into the fix for 2: After get blobs completes, we not only publish anything in the partial assembler, but also for every missing custody column in there, publish an empty column and a request for all cells.

In particular:
- When sending a partial message to `network`, allow specifying a request bitmap instead of hardcoding an all-ones bitmap.
- For clarity and to prepare for Gloas integration, add a `PubsubPartialMessage` enum with a `DataColumnFulu` variant.
- On republishing after merging a gossip column: always publish, but only request cells if local blobs are known or get blobs is disabled. This also prepares us to request only *some* cells, e.g. in cases where we are aware of the blobs that the EL is going to send us, e.g. via `engine_hasBlobs`.
- Move guards in `fetch_engine_blobs_and_publish` to ensure everything works fine if there are no blobs or if get_blobs is disabled.


Co-Authored-By: Daniel Knopik <daniel@dknopik.de>

beacon_node/beacon_chain/src/fetch_blobs/tests.rs

@@ -344,7 +344,7 @@ fn mock_beacon_adapter(fork_name: ForkName, get_blobs_v3: bool) -> MockFetchBlob
     let test_runtime = TestRuntime::default();
     let spec = Arc::new(fork_name.make_genesis_spec(E::default_spec()));
     let kzg = get_kzg(&spec);
-    let partial_assembler = PartialDataColumnAssembler::new(32);
+    let partial_assembler = PartialDataColumnAssembler::new(32, false);
 
     let mut mock_adapter = MockFetchBlobsBeaconAdapter::default();
     mock_adapter.expect_spec().return_const(spec.clone());