Defer captcha script loading (go-gitea#33919)

Fix go-gitea#33899

(cherry picked from commit fdaf1cc)

Author: wxiaoguang

templates/user/auth/captcha.tmpl

@@ -11,12 +11,12 @@
 	<div class="inline field tw-text-center required">
 		<div id="captcha" data-captcha-type="g-recaptcha" class="g-recaptcha-style" data-sitekey="{{.RecaptchaSitekey}}"></div>
 	</div>
-	<script src='{{URLJoin .RecaptchaURL "api.js"}}'></script>
+	<script defer src='{{URLJoin .RecaptchaURL "api.js"}}'></script>
 {{else if eq .CaptchaType "hcaptcha"}}
 	<div class="inline field tw-text-center required">
 		<div id="captcha" data-captcha-type="h-captcha" class="h-captcha-style" data-sitekey="{{.HcaptchaSitekey}}"></div>
 	</div>
-	<script src='https://hcaptcha.com/1/api.js'></script>
+	<script defer src='https://hcaptcha.com/1/api.js'></script>
 {{else if eq .CaptchaType "mcaptcha"}}
 	<div class="inline field tw-text-center">
 		<div class="m-captcha-style" id="mcaptcha__widget-container"></div>
@@ -26,5 +26,5 @@
 	<div class="inline field tw-text-center">
 		<div id="captcha" data-captcha-type="cf-turnstile" data-sitekey="{{.CfTurnstileSitekey}}"></div>
 	</div>
-	<script src='https://challenges.cloudflare.com/turnstile/v0/api.js'></script>
+	<script defer src='https://challenges.cloudflare.com/turnstile/v0/api.js'></script>
 {{end}}{{end}}