[MM-32622] Remove app.WaitForChannelMembership() (#17048)

* Remove app.WaitForChannelMembership

* Fix tests

* Fix test

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

api4/channel_test.go

@@ -4,6 +4,7 @@
 package api4
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"sort"
@@ -2491,7 +2492,7 @@ func TestUpdateChannelNotifyProps(t *testing.T) {
 	CheckNoError(t, resp)
 	require.True(t, pass, "should have passed")
 
-	member, err := th.App.GetChannelMember(th.BasicChannel.Id, th.BasicUser.Id)
+	member, err := th.App.GetChannelMember(context.Background(), th.BasicChannel.Id, th.BasicUser.Id)
 	require.Nil(t, err)
 	require.Equal(t, model.CHANNEL_NOTIFY_MENTION, member.NotifyProps[model.DESKTOP_NOTIFY_PROP], "bad update")
 	require.Equal(t, model.CHANNEL_MARK_UNREAD_MENTION, member.NotifyProps[model.MARK_UNREAD_NOTIFY_PROP], "bad update")