fix: Correct arraycopy source and destination in dropRow method

- Fixed the source and destination parameters in `System.arraycopy` to correctly handle the dropping of a row from the matrix.
- The source was incorrectly set to `newEntries[destRow++]`, which is now updated to `entries[i]`, and the destination is updated to `newEntries[destRow++]`.

Author: mitsuki31

src/main/java/com/mitsuki/jmatrix/Matrix.java

@@ -1279,7 +1279,7 @@ public static Matrix dropRow(Matrix m, int row) {
         double[][] newEntries = new double[rows - 1][cols];
         for (int i = 0, destRow = 0; i < rows; i++) {
             if (i == row) continue;  // Skip the desired row index
-            System.arraycopy(newEntries[destRow++], 0, entries[i], 0, cols);
+            System.arraycopy(entries[i], 0, newEntries[destRow++], 0, cols);
         }
 
         return new Matrix(newEntries);