refactor(log): replace log.Critical with log.Error (#37624)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: wxiaoguang <2114189+wxiaoguang@users.noreply.github.com>

cmd/web.go

@@ -150,7 +150,7 @@ func serveInstall(cmd *cli.Command) error {
 	c := install.Routes()
 	err := listen(c, false)
 	if err != nil {
-		log.Critical("Unable to open listener for installer. Is Gitea already running?")
+		log.Error("Unable to open listener for installer. Is Gitea already running?")
 		graceful.GetManager().DoGracefulShutdown()
 	}
 	select {
@@ -375,7 +375,7 @@ func listen(m http.Handler, handleRedirector bool) error {
 		log.Fatal("Invalid protocol: %s", setting.Protocol)
 	}
 	if err != nil {
-		log.Critical("Failed to start server: %v", err)
+		log.Error("Failed to start server: %v", err)
 	}
 	log.Info("HTTP Listener: %s Closed", listenAddr)
 	return err