Fix flaky 'wait_for_the_expected_time' test

Author: jpraynaud

mithril-test-lab/mithril-end-to-end/src/utils/spec_utils.rs

@@ -97,7 +97,7 @@ mod tests {
 
         let elapsed = now.elapsed().as_millis();
         assert!(
-            (10..=15).contains(&elapsed),
+            (10..=30).contains(&elapsed),
             "Failure, after one loop the elapsed time was not ~10ms, elapsed: {elapsed}"
         );
     }