fix: remove double/unintended `free` (#1143)

The call to realloc() already frees the previously allocated memory if necessary.
By the man page of realloc(): "f the area pointed to was moved, a free(ptr) is done.",
and free(): "If free(ptr) has already been called before, undefined behavior occurs.".

data_structures/dynamic_array/dynamic_array.c

@@ -18,7 +18,6 @@ void *add(dynamic_array_t *da, const void *value)
     {
         void **newItems =
             realloc(da->items, (da->capacity <<= 1) * sizeof(void **));
-        free(da->items);
 
         da->items = newItems;
     }
@@ -79,4 +78,4 @@ void *retrive_copy_of_value(const void *value)
     memcpy(value_copy, value, sizeof(void *));
 
     return value_copy;
-}
+}