fix bug when there is an empty line in mc admin response

`json.loads(line)` would throw an error if line is empty (e.g. `line == ''`).
To fix it, simply check if line is truthy (i.e. not empty).

Also, `text=True` is passed `subprocess.run` to ensure `proc.stdout` is a string
and not bytes object.

minio/minioadmin.py

@@ -48,9 +48,10 @@ def _run(self, args, multiline=False):
             capture_output=True,
             timeout=self._timeout,
             check=True,
+            text=True,
         )
         if multiline:
-            return [json.loads(line) for line in proc.stdout.split("\n")]
+            return [json.loads(line) for line in proc.stdout.split("\n") if line]
         return json.loads(proc.stdout)
 
     def service_restart(self):