add missing fields to get blob sidecars request (#5987)

* add missing fields to get blob sidecars request

* add fork versioned  response impl

* only compute the block root once

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into add-missing-fields-get-blob-sidecars

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into add-missing-fields-get-blob-sidecars

* fetch root first

fetch from cache if its a head block

* fmt

* always load from db

common/eth2/src/lib.rs

@@ -1141,7 +1141,8 @@ impl BeaconNodeHttpClient {
         &self,
         block_id: BlockId,
         indices: Option<&[u64]>,
-    ) -> Result<Option<GenericResponse<BlobSidecarList<E>>>, Error> {
+    ) -> Result<Option<ExecutionOptimisticFinalizedForkVersionedResponse<BlobSidecarList<E>>>, Error>
+    {
         let mut path = self.get_blobs_path(block_id)?;
         if let Some(indices) = indices {
             let indices_string = indices