Run test_unittest in the lazy_imports=all job

The fix makes it pass: unittest/__init__.py does "from .main import main",
and an import of unittest.main elsewhere replaced the function with the
submodule.

Assisted-By: Claude Opus 5.5

Author: Lillecarl

Lib/test/lazy_imports_all_exclude.txt

@@ -36,4 +36,3 @@ test_subprocess
 test_symtable
 test_tools
 test_type_annotations
-test_unittest