LibWeb+WebContent+WebDriver: Implement Get Alert Text

Author: https://github.com/trflynn89
Commit: f9b8742fff
Pull-request: https://github.com/SerenityOS/serenity/pull/16091
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibWeb/WebDriver/Client.cpp

@@ -95,6 +95,7 @@ static constexpr auto s_webdriver_endpoints = Array {
     ROUTE(DELETE, "/session/:session_id/cookie"sv, delete_all_cookies),
     ROUTE(POST, "/session/:session_id/alert/dismiss"sv, dismiss_alert),
     ROUTE(POST, "/session/:session_id/alert/accept"sv, accept_alert),
+    ROUTE(GET, "/session/:session_id/alert/text"sv, get_alert_text),
     ROUTE(GET, "/session/:session_id/screenshot"sv, take_screenshot),
     ROUTE(GET, "/session/:session_id/element/:element_id/screenshot"sv, take_element_screenshot),
 };