Remove size check in CDKGSessionManager::GetVerifiedContributions

It's actually not true that these should always be the same. In case a
quorum is built and the total number of masternodes in the network is below
the quorum size, we might still end up having a valid quorum as long as
the total number of masternodes is >= minSize.

src/llmq/quorums_dkgsessionmgr.cpp

@@ -216,11 +216,6 @@ bool CDKGSessionManager::GetVerifiedContributions(Consensus::LLMQType llmqType,
 {
     auto members = CLLMQUtils::GetAllQuorumMembers(llmqType, quorumHash);
 
-    if (validMembers.size() != members.size()) {
-        // should never happen as we should always call this method with correct params
-        return false;
-    }
-
     memberIndexesRet.clear();
     vvecsRet.clear();
     skContributionsRet.clear();