[MM-46694] A/B Test: welcome post (#20926)

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

model/feature_flags.go

@@ -72,6 +72,9 @@ type FeatureFlags struct {
 
 	PlanUpgradeButtonText string
 
+	// A/B Test on posting a welcome message
+	SendWelcomePost bool
+
 	PostPriority bool
 }
 
@@ -99,6 +102,7 @@ func (f *FeatureFlags) SetDefaults() {
 	f.CallsEnabled = true
 	f.BoardsProduct = false
 	f.PlanUpgradeButtonText = "upgrade"
+	f.SendWelcomePost = true
 	f.PostPriority = false
 }