MM-57532: Improve timeouts for some tests (#26642)

- Bump timeouts for some cases
- Improve sleep with require/assert.EventuallyT
for better performance and reliability.

https://mattermost.atlassian.net/browse/MM-57532

```release-note
NONE
```

server/channels/api4/user_test.go

@@ -6590,7 +6590,7 @@ func TestThreadSocketEvents(t *testing.T) {
 							}
 						}
 					}
-				case <-time.After(1 * time.Second):
+				case <-time.After(2 * time.Second):
 					return
 				}
 			}
@@ -6613,7 +6613,7 @@ func TestThreadSocketEvents(t *testing.T) {
 						require.Equal(t, ev.GetData()["state"], false)
 						require.Equal(t, ev.GetData()["reply_count"], float64(1))
 					}
-				case <-time.After(1 * time.Second):
+				case <-time.After(2 * time.Second):
 					return
 				}
 			}
@@ -6641,7 +6641,7 @@ func TestThreadSocketEvents(t *testing.T) {
 						require.EqualValues(t, float64(0), data["unread_replies"])
 						require.EqualValues(t, float64(0), data["unread_mentions"])
 					}
-				case <-time.After(1 * time.Second):
+				case <-time.After(2 * time.Second):
 					return
 				}
 			}
@@ -6670,7 +6670,7 @@ func TestThreadSocketEvents(t *testing.T) {
 						require.EqualValues(t, float64(1), data["unread_replies"])
 						require.EqualValues(t, float64(1), data["unread_mentions"])
 					}
-				case <-time.After(1 * time.Second):
+				case <-time.After(2 * time.Second):
 					return
 				}
 			}
@@ -6758,7 +6758,7 @@ func TestThreadSocketEvents(t *testing.T) {
 							require.Equal(t, tc.replies, thread.UnreadReplies)
 							require.Equal(t, tc.mentions, thread.UnreadMentions)
 						}
-					case <-time.After(1 * time.Second):
+					case <-time.After(2 * time.Second):
 						return
 					}
 				}
@@ -6803,7 +6803,7 @@ func TestThreadSocketEvents(t *testing.T) {
 						require.Equal(t, int64(3), thread.UnreadReplies)
 						require.Equal(t, int64(1), thread.UnreadMentions)
 					}
-				case <-time.After(1 * time.Second):
+				case <-time.After(2 * time.Second):
 					return
 				}
 			}