Fix flaky MLS conversation creation test (#2386)

The assertion was (very rarely) picking up a connection event between
alice and bob, and failing. Since bob is irrelevant to the test, this
commit removes bob and the related assertion altogether.

changelog.d/5-internal/mls-flaky-conversation

@@ -0,0 +1 @@
+Fix flaky MLS conversation creation test

services/galley/test/integration/API/MLS.hs

@@ -96,17 +96,14 @@ postMLSConvOk :: TestM ()
 postMLSConvOk = do
   c <- view tsCannon
   qalice <- randomQualifiedUser
-  bob <- randomUser
   let alice = qUnqualified qalice
   let nameMaxSize = T.replicate 256 "a"
-  connectUsers alice (list1 bob [])
-  WS.bracketR2 c alice bob $ \(wsA, wsB) -> do
+  WS.bracketR c alice $ \wsA -> do
     rsp <- postConvQualified alice defNewMLSConv {newConvName = checked nameMaxSize}
     pure rsp !!! do
       const 201 === statusCode
       const Nothing === fmap Wai.label . responseJsonError
     cid <- assertConv rsp RegularConv alice qalice [] (Just nameMaxSize) Nothing
-    WS.assertNoEvent (2 # WS.Second) [wsB]
     checkConvCreateEvent cid wsA
 
 testLocalWelcome :: TestM ()