Bump Go version to 1.23.6 (#30242)

* Bump Go version to 1.23.6

* Update CodeQL Github action as well

* Use server's Go version for CodeQL action

Co-authored-by: Antonis Stamatiou <stamatiou.antonis@gmail.com>

* Empty commit to trigger CI

* Bump golangci-lint to a version supporting Go 1.23

* Fix golangci-lint warnings

Several rules from gosimple, revive and staticcheck linters were
failing:
- Redefinition of built-in identifiers (max, min, new, recover...)
- Use of printf-like functions with simple strings
- Check for nil slices, when len already takes it into account

---------

Co-authored-by: Antonis Stamatiou <stamatiou.antonis@gmail.com>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/plugin.go

@@ -237,10 +237,10 @@ func (ch *Channels) initPlugins(c request.CTX, pluginDir, webappPluginDir string
 	// Sync plugin active state when config changes. Also notify plugins.
 	ch.pluginsLock.Lock()
 	ch.RemoveConfigListener(ch.pluginConfigListenerID)
-	ch.pluginConfigListenerID = ch.AddConfigListener(func(old, new *model.Config) {
+	ch.pluginConfigListenerID = ch.AddConfigListener(func(oldCfg, newCfg *model.Config) {
 		// If plugin status remains unchanged, only then run this.
 		// Because (*App).InitPlugins is already run as a config change hook.
-		if *old.PluginSettings.Enable == *new.PluginSettings.Enable {
+		if *oldCfg.PluginSettings.Enable == *newCfg.PluginSettings.Enable {
 			ch.syncPluginsActiveState()
 		}