Return code is not very useful to assume a task failed

So I thought I fixed it before, but there's still one location where
the `rc` value is influential to decide whether a task failed or not.

We already established in #24867 that it is up to the module to decide
what the return code actually means, not the task executor. We modified
the existing modules to move that logic into the module (eg. for
command, shell, etc.)

This relates to the integration tests of win_robocopy, where different
return codes have different meanings:

  - 0  --  No files copied.
  - 1  --  Files copied successfully! (changed)
  - 2  --  Some Extra files or directories were detected. No files were copied. (warning)
  - 3  --  (2+1) Some files were copied. Additional files were present. (changed)
  - 4  --  Some mismatched files or directories were detected. Housekeeping might be required!  (changed + warning)
  - 5  --  (4+1) Some files were copied. Some files were mismatched.  (changed + warning)
  - 6  --  (4+2) Additional files and mismatched files exist.  No files were copied. (warning)
  - 7  --  (4+1+2) Files were copied, a file mismatch was present, and additional files were present. (changed + warning)
  - 8  --  Some files or directories could not be copied! (changed + failed)
  - 9 - 15  --  Fatal error. Check log message! (failed)
  - 16  --  Serious Error! No files were copied! Do you have permissions to access $src and $dest? (failed)

This also fixes #24652

lib/ansible/executor/task_result.py

@@ -67,7 +67,7 @@ class TaskResult:
            'results' in self._result and True in [True for x in self._result['results'] if 'failed_when_result' in x]:
             return self._check_key('failed_when_result')
         else:
-            return self._check_key('failed') or self._result.get('rc', 0) != 0
+            return self._check_key('failed')
 
     def is_unreachable(self):
         return self._check_key('unreachable')

test/units/executor/test_task_result.py

@@ -125,11 +125,11 @@ class TestTaskResult(unittest.TestCase):
         tr = TaskResult(mock_host, mock_task, dict())
         self.assertFalse(tr.is_failed())
 
-        # test failed result with rc values
+        # test failed result with rc values (should not matter)
         tr = TaskResult(mock_host, mock_task, dict(rc=0))
         self.assertFalse(tr.is_failed())
         tr = TaskResult(mock_host, mock_task, dict(rc=1))
-        self.assertTrue(tr.is_failed())
+        self.assertFalse(tr.is_failed())
 
         # test with failed in result
         tr = TaskResult(mock_host, mock_task, dict(failed=True))