Add system console switch for enabling link previews (#5663)

utils/config.go

@@ -267,6 +267,7 @@ func getClientConfig(c *model.Config) map[string]string {
 	props["EnableOnlyAdminIntegrations"] = strconv.FormatBool(*c.ServiceSettings.EnableOnlyAdminIntegrations)
 	props["EnablePostUsernameOverride"] = strconv.FormatBool(c.ServiceSettings.EnablePostUsernameOverride)
 	props["EnablePostIconOverride"] = strconv.FormatBool(c.ServiceSettings.EnablePostIconOverride)
+	props["EnableLinkPreviews"] = strconv.FormatBool(*c.ServiceSettings.EnableLinkPreviews)
 	props["EnableTesting"] = strconv.FormatBool(c.ServiceSettings.EnableTesting)
 	props["EnableDeveloper"] = strconv.FormatBool(*c.ServiceSettings.EnableDeveloper)
 	props["EnableDiagnostics"] = strconv.FormatBool(*c.LogSettings.EnableDiagnostics)