[MM-30851] Replace ExperimentalChannelSidebarOrganization with EnableLegacySidebar (#16529)

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

config/client.go

@@ -61,7 +61,6 @@ func GenerateClientConfig(c *model.Config, telemetryID string, license *model.Li
 		props["ExperimentalChannelOrganization"] = strconv.FormatBool(false)
 	}
 
-	props["ExperimentalChannelSidebarOrganization"] = *c.ServiceSettings.ExperimentalChannelSidebarOrganization
 	props["ExperimentalEnableAutomaticReplies"] = strconv.FormatBool(*c.TeamSettings.ExperimentalEnableAutomaticReplies)
 	props["ExperimentalTimezone"] = strconv.FormatBool(*c.DisplaySettings.ExperimentalTimezone)
 
@@ -99,6 +98,8 @@ func GenerateClientConfig(c *model.Config, telemetryID string, license *model.Li
 
 	props["CloudUserLimit"] = strconv.FormatInt(*c.ExperimentalSettings.CloudUserLimit, 10)
 
+	props["EnableLegacySidebar"] = strconv.FormatBool(*c.ServiceSettings.EnableLegacySidebar)
+
 	// Set default values for all options that require a license.
 	props["ExperimentalHideTownSquareinLHS"] = "false"
 	props["ExperimentalTownSquareIsReadOnly"] = "false"