ble_adafruit_simpletest_client.py seems to stuck on a value

Received value get frozen to a fix value after a few update.

Test condition:
- CLUE running a client similar to ble_adafruit_simpletest_client.py (with light rather than temperature).
- Feather Sense running ble_adafruit_feather_bluefruit_sense.py
- Flash Light moving in front of the Sense Light sensor.

After a few update working, the CLUE only display the same value again and again whatever you do with the Flash Light.
Between each test I did a reset or a power off of the CLUE (playing with CTRL-C and CTRL-D was not working either, but I had other issue like "not connected" error, so I wanted to simplify the test condition).

I had fix, but it should work without it: #9

Regards

Reproduce the freeze with ble_adafruit_simpletest_client.py on the CLUE and ble_adafruit_feather_bluefruit_sense.py on the Feather Sense, using the light sensor setup described. Compare the behavior with the fix in issue #9 and verify that repeated updates reflect changes from the flashlight without requiring a reset.

Written by the indexing model from the issue text.