Increase implicit suite timeout to 40 mins (#72495)

The MixedClusterClientYamlTestSuiteIT test suite has been ordained with a 40 mins timeout.
But the ElasticsearchTestBasePlugin overrides the suite annotation,
using a system prop, to 30 mins; see also SysGlobals#SYSPROP_TIMEOUT_SUITE .
This PR increases the value for the system prop override to 40 mins,
to match the above suites declarations.

Closes #72393

buildSrc/src/main/java/org/elasticsearch/gradle/internal/ElasticsearchTestBasePlugin.java

@@ -176,7 +176,7 @@ public void execute(Task t) {
 
             if (OS.current().equals(OS.WINDOWS) && System.getProperty("tests.timeoutSuite") == null) {
                 // override the suite timeout to 30 mins for windows, because it has the most inefficient filesystem known to man
-                test.systemProperty("tests.timeoutSuite", "1800000!");
+                test.systemProperty("tests.timeoutSuite", "2400000!");
             }
 
             /*