Fix linters (#808)

Signed-off-by: Crola1702 <[email protected]>

Author: Crola1702

ros2cli/ros2cli/helpers.py

@@ -43,6 +43,7 @@ def wait_for(predicate, timeout, period=0.1):
         time.sleep(period)
     return True
 
+
 def bind(func, *args, **kwargs):
     """
     Bind a function with a set of arguments.

ros2node/ros2node/api/__init__.py

@@ -12,8 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import time
-
 from collections import namedtuple
 from typing import Any
 from typing import List