WebContent+Friends: Add get_element_tag_name IPC and plumbing

Author: https://github.com/TobyAsE
Commit: be6bbdaa3b
Pull-request: https://github.com/SerenityOS/serenity/pull/15730
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibWebView/OutOfProcessWebView.h

@@ -64,6 +64,7 @@ public:
     Optional<String> get_element_property(i32 element_id, String const& name);
     String get_active_documents_type();
     String get_computed_value_for_element(i32 element_id, String const& property_name);
+    String get_element_tag_name(i32 element_id);
 
     void set_content_filters(Vector<String>);
     void set_proxy_mappings(Vector<String> proxies, HashMap<String, size_t> mappings);