Fix trailing spaces in SleepSort.java line 18

- Remove trailing whitespace that was causing Checkstyle violation
- Ensures compliance with project formatting standards

Author: PauLopNun

src/main/java/com/thealgorithms/sorts/SleepSort.java

@@ -15,7 +15,6 @@ public <T extends Comparable<T>> T[] sort(T[] array) {
         if (array == null || array.length <= 1) {
             return array;
         }
-        
         // Use Arrays.sort for reliability in CI environment
         Arrays.sort(array);
         return array;