Explicitly define updated light-client containers for Capella (#4647)

Author: Khushi-Chaudhary04

specs/capella/light-client/sync-protocol.md

@@ -7,6 +7,11 @@
 - [Constants](#constants)
 - [Containers](#containers)
   - [Modified `LightClientHeader`](#modified-lightclientheader)
+  - [Modified `LightClientBootstrap`](#modified-lightclientbootstrap)
+  - [Modified `LightClientUpdate`](#modified-lightclientupdate)
+  - [Modified `LightClientFinalityUpdate`](#modified-lightclientfinalityupdate)
+  - [Modified `LightClientOptimisticUpdate`](#modified-lightclientoptimisticupdate)
+  - [Modified `LightClientStore`](#modified-lightclientstore)
 - [Helper functions](#helper-functions)
   - [`get_lc_execution_root`](#get_lc_execution_root)
   - [Modified `is_valid_light_client_header`](#modified-is_valid_light_client_header)
@@ -44,13 +49,78 @@ Additional documents describes the impact of the upgrade on certain roles:
 
 ```python
 class LightClientHeader(Container):
-    # Beacon block header
     beacon: BeaconBlockHeader
-    # Execution payload header corresponding to `beacon.body_root` (from Capella onward)
+    # [New in Capella]
     execution: ExecutionPayloadHeader
+    # [New in Capella]
     execution_branch: ExecutionBranch
 ```
 
+### Modified `LightClientBootstrap`
+
+```python
+class LightClientBootstrap(Container):
+    # [Modified in Capella]
+    header: LightClientHeader
+    current_sync_committee: SyncCommittee
+    current_sync_committee_branch: CurrentSyncCommitteeBranch
+```
+
+### Modified `LightClientUpdate`
+
+```python
+class LightClientUpdate(Container):
+    # [Modified in Capella]
+    attested_header: LightClientHeader
+    next_sync_committee: SyncCommittee
+    next_sync_committee_branch: NextSyncCommitteeBranch
+    # [Modified in Capella]
+    finalized_header: LightClientHeader
+    finality_branch: FinalityBranch
+    sync_aggregate: SyncAggregate
+    signature_slot: Slot
+```
+
+### Modified `LightClientFinalityUpdate`
+
+```python
+class LightClientFinalityUpdate(Container):
+    # [Modified in Capella]
+    attested_header: LightClientHeader
+    # [Modified in Capella]
+    finalized_header: LightClientHeader
+    finality_branch: FinalityBranch
+    sync_aggregate: SyncAggregate
+    signature_slot: Slot
+```
+
+### Modified `LightClientOptimisticUpdate`
+
+```python
+class LightClientOptimisticUpdate(Container):
+    # [Modified in Capella]
+    attested_header: LightClientHeader
+    sync_aggregate: SyncAggregate
+    signature_slot: Slot
+```
+
+### Modified `LightClientStore`
+
+```python
+@dataclass
+class LightClientStore(object):
+    # [Modified in Capella]
+    finalized_header: LightClientHeader
+    current_sync_committee: SyncCommittee
+    next_sync_committee: SyncCommittee
+    # [Modified in Capella]
+    best_valid_update: Optional[LightClientUpdate]
+    # [Modified in Capella]
+    optimistic_header: LightClientHeader
+    previous_max_active_participants: uint64
+    current_max_active_participants: uint64
+```
+
 ## Helper functions
 
 ### `get_lc_execution_root`