fix: handle null and empty array in LinearSearch (issue #7340) (#7347)

Author: Senrian

src/main/java/com/thealgorithms/searches/LinearSearch.java

@@ -41,10 +41,13 @@ public class LinearSearch implements SearchAlgorithm {
      *
      * @param array List to be searched
      * @param value Key being searched for
-     * @return Location of the key
+     * @return Location of the key, -1 if array is null or empty, or key not found
      */
     @Override
     public <T extends Comparable<T>> int find(T[] array, T value) {
+        if (array == null || array.length == 0) {
+            return -1;
+        }
         for (int i = 0; i < array.length; i++) {
             if (array[i].compareTo(value) == 0) {
                 return i;