[MM-59060] Remove pre release features section from advanced section of user settings (#27608)

server/config/client.go

@@ -41,7 +41,6 @@ func GenerateClientConfig(c *model.Config, telemetryID string, license *model.Li
 	props["EnableClientPerformanceDebugging"] = strconv.FormatBool(*c.ServiceSettings.EnableClientPerformanceDebugging)
 	props["PostEditTimeLimit"] = strconv.Itoa(*c.ServiceSettings.PostEditTimeLimit)
 	props["MinimumHashtagLength"] = strconv.Itoa(*c.ServiceSettings.MinimumHashtagLength)
-	props["EnablePreviewFeatures"] = strconv.FormatBool(*c.ServiceSettings.EnablePreviewFeatures)
 	props["EnableTutorial"] = strconv.FormatBool(*c.ServiceSettings.EnableTutorial)
 	props["EnableOnboardingFlow"] = strconv.FormatBool(*c.ServiceSettings.EnableOnboardingFlow)
 	props["ExperimentalEnableDefaultChannelLeaveJoinMessages"] = strconv.FormatBool(*c.ServiceSettings.ExperimentalEnableDefaultChannelLeaveJoinMessages)