docs: Fix example in MyCustomDsl to remove throws Exception

In `init` and `configure`, throws Exception has been removed in the super interface `SecurityConfigurer`, since Spring Security 7.0.
This change is the consequence of #17957

Signed-off-by: Guillaume Husta <guillaume.husta@gmail.com>

Author: ghusta

docs/modules/ROOT/pages/servlet/configuration/java.adoc

@@ -493,14 +493,14 @@ public class MyCustomDsl extends AbstractHttpConfigurer<MyCustomDsl, HttpSecurit
 	private boolean flag;
 
 	@Override
-	public void init(HttpSecurity http) throws Exception {
+	public void init(HttpSecurity http) {
 		// any method that adds another configurer
 		// must be done in the init method
 		http.csrf().disable();
 	}
 
 	@Override
-	public void configure(HttpSecurity http) throws Exception {
+	public void configure(HttpSecurity http) {
 		ApplicationContext context = http.getSharedObject(ApplicationContext.class);
 
 		// here we lookup from the ApplicationContext. You can also just create a new instance.