CheckContainers fails on a Raspbian Bullseye 64 bit

[riklempens]

CheckContainers fails while running the Docker agent on Raspbian version Bullseye 64 bit.

The following error is logged:

[E 230521 06:48:36 base:43] 
Traceback (most recent call last):
  File "/code/lib/check/base.py", line 33, in run
    data = await asyncio.wait_for(
  File "/usr/local/lib/python3.9/asyncio/tasks.py", line 479, in wait_for
    return fut.result()
  File "/code/lib/check/checkContainers.py", line 116, in get_data
    cls.apply_stats(state_data['containers'], stats)
  File "/code/lib/check/checkContainers.py", line 181, in apply_stats
    memory = cls.calculate_memory_percentage(istats)
  File "/code/lib/check/checkContainers.py", line 40, in calculate_memory_percentage
    used_memory = memory_stats['usage'] - stats.get(
KeyError: 'usage'
[E 230521 06:48:36 agent:228] check error (containers): 'usage'