MM-53107 Add setting to limit the max number of markdown nodes (#24414)

* MM-53107 Add setting to limit the max number of markdown nodes

* Add extra validation for a couple config fields

* Add new setting to telemetry

server/config/client.go

@@ -130,6 +130,7 @@ func GenerateClientConfig(c *model.Config, telemetryID string, license *model.Li
 	props["DataRetentionFileRetentionDays"] = "0"
 
 	props["CustomUrlSchemes"] = strings.Join(c.DisplaySettings.CustomURLSchemes, ",")
+	props["MaxMarkdownNodes"] = strconv.FormatInt(int64(*c.DisplaySettings.MaxMarkdownNodes), 10)
 	props["IsDefaultMarketplace"] = strconv.FormatBool(*c.PluginSettings.MarketplaceURL == model.PluginSettingsDefaultMarketplaceURL)
 	props["ExperimentalSharedChannels"] = "false"
 	props["CollapsedThreads"] = *c.ServiceSettings.CollapsedThreads