Fix bloom filter expectations in group chat test

Every peer must be subscribed to the topic that is used to send messages.
In the test Alice was communicating with Bob and Charlie over custom topic, but
that topic wasn't added to a bloom filter, thus a certain flake was possible.

Normally it wasn't causing problems because syncAllowance in whisper, which is 10s:
- we set bloom filter to all zeros
- but we still will accept all envelopes for 10s
- in case we send first envelope into such channel after sync allowance - we will get an error such
that envelope doesn't match the bloom filter

t/e2e/whisper/whisper_mailbox_test.go

@@ -201,6 +201,12 @@ func (s *WhisperMailboxSuite) TestRequestMessagesInGroupChat() {
 	charliePubkey := hexutil.Bytes(crypto.FromECDSAPub(&charlieKey.PublicKey))
 	charlieAliceKeySendTopic := whisper.BytesToTopic([]byte("charlieAliceKeySendTopic "))
 
+	// Alice must add peers topics into her own bloom filter.
+	aliceKeyID, err := aliceWhisperService.NewKeyPair()
+	s.Require().NoError(err)
+	s.createPrivateChatMessageFilter(aliceRPCClient, aliceKeyID, bobAliceKeySendTopic.String())
+	s.createPrivateChatMessageFilter(aliceRPCClient, aliceKeyID, charlieAliceKeySendTopic.String())
+
 	// Bob and charlie create message filter.
 	bobMessageFilterID := s.createPrivateChatMessageFilter(bobRPCClient, bobKeyID, bobAliceKeySendTopic.String())
 	charlieMessageFilterID := s.createPrivateChatMessageFilter(charlieRPCClient, charlieKeyID, charlieAliceKeySendTopic.String())