statement-distribution: validator disabling (#1841)

Closes #1591.

The purpose of this PR is filter out backing statements from the network
signed by disabled validators. This is just an optimization, since we
will do filtering in the runtime in #1863 to avoid nodes to filter
garbage out at block production time.

- [x] Ensure it's ok to fiddle with the mask of manifests
- [x] Write more unit tests
- [x] Test locally
- [x] simple zombienet test
- [x] PRDoc

---------

Co-authored-by: Tsvetomir Dimitrov <[email protected]>

.gitlab/pipeline/zombienet/polkadot.yml

@@ -139,6 +139,14 @@ zombienet-polkadot-functional-0009-approval-voting-coalescing:
       --local-dir="${LOCAL_DIR}/functional"
       --test="0009-approval-voting-coalescing.zndsl"
 
+zombienet-polkadot-functional-0010-validator-disabling:
+  extends:
+    - .zombienet-polkadot-common
+  script:
+    - /home/nonroot/zombie-net/scripts/ci/run-test-local-env-manager.sh
+      --local-dir="${LOCAL_DIR}/functional"
+      --test="0010-validator-disabling.zndsl"
+
 zombienet-polkadot-smoke-0001-parachains-smoke-test:
   extends:
     - .zombienet-polkadot-common

polkadot/node/network/statement-distribution/src/error.rs

@@ -75,6 +75,9 @@ pub enum Error {
 	#[error("Fetching availability cores failed {0:?}")]
 	FetchAvailabilityCores(RuntimeApiError),
 
+	#[error("Fetching disabled validators failed {0:?}")]
+	FetchDisabledValidators(runtime::Error),
+
 	#[error("Fetching validator groups failed {0:?}")]
 	FetchValidatorGroups(RuntimeApiError),
 

polkadot/node/network/statement-distribution/src/v2/grid.rs

@@ -253,7 +253,9 @@ impl GridTracker {
 	/// This checks whether the peer is allowed to send us manifests
 	/// about this group at this relay-parent. This also does sanity
 	/// checks on the format of the manifest and the amount of votes
-	/// it contains. It has effects on the stored state only when successful.
+	/// it contains. It assumes that the votes from disabled validators
+	/// are already filtered out.
+	/// It has effects on the stored state only when successful.
 	///
 	/// This returns a `bool` on success, which if true indicates that an acknowledgement is
 	/// to be sent in response to the received manifest. This only occurs when the