chore(concat_string_test): move to right repository

sh/tests/concat_string_test.py

@@ -1,13 +0,0 @@
-import sys
-
-sys.path.append('student')
-
-from concat_string import concat
-
-def test_concat():
-    assert concat("Hello", "World") == "Hello, World"
-    assert concat("Hi", "there") == "Hi, there"
-    assert concat("", "") == ", "
-    assert concat("Hello", "") == "Hello, "
-    assert concat("", "World") == ", World"
-test_concat()