Attempt to run a container scenario for api while count is bigger than 1 results in crash about krkn HOT 1 OPEN

Same behavior reproduced with killing etcd:

`
chaos_scenarios: # List of policies/chaos scenarios to load
- container_scenarios: # List of chaos pod scenarios to load
- - scenarios/openshift/container_etcd.yml

`

`
scenarios:

• name: "kill etcd container"
  namespace: "openshift-etcd"
  label_selector: "k8s-app=etcd"
  container_name: "etcd"
  action: "kill 1"
  count: 1
  expected_recovery_time: 60
  `

python3.9 run_kraken.py --config config/kill-etcd.yaml _ _ | | ___ __ __ _| | _____ _ __ | |/ / '__/ _ | |/ / _ \ '_ \
| <| | | (| | < __/ | | |
||__| _,||____|| |_|

2023-05-25 12:23:02,066 [INFO] Starting kraken
2023-05-25 12:23:02,075 [INFO] Initializing client to talk to the Kubernetes cluster
2023-05-25 12:23:05,649 [INFO] Publishing kraken status at http://0.0.0.0:8085
2023-05-25 12:23:05,649 [INFO] Publishing kraken status at http://0.0.0.0:8085
2023-05-25 12:23:05,650 [INFO] Starting http server at http://0.0.0.0:8085

2023-05-25 12:23:05,650 [INFO] Fetching cluster info
2023-05-25 12:23:05,658 [INFO] Cluster version is 4.13.0
2023-05-25 12:23:05,659 [INFO] Server URL: https://api.elvis2.qe.lab.redhat.com:6443
2023-05-25 12:23:05,659 [INFO] Generated a uuid for the run: 77d465f6-2149-4233-b9f7-4642e84dffb0
2023-05-25 12:23:05,659 [INFO] Daemon mode not enabled, will run through 1 iterations

2023-05-25 12:23:05,659 [INFO] Executing scenarios for iteration 0
2023-05-25 12:23:05,659 [INFO] connection set up
127.0.0.1 - - [25/May/2023 12:23:05] "GET / HTTP/1.1" 200 -
2023-05-25 12:23:05,660 [INFO] response RUN
2023-05-25 12:23:05,660 [INFO] Running container scenarios
2023-05-25 12:23:08,343 [INFO] Killing container etcd in pod etcd-master-1-2 (ns openshift-etcd)
2023-05-25 12:23:08,466 [INFO] Killing container etcd in pod etcd-master-1-1 (ns openshift-etcd)
2023-05-25 12:23:08,657 [INFO] Scenario kill etcd container successfully injected
Traceback (most recent call last):
File "/root/krkn/krkn/run_kraken.py", line 421, in
main(options.cfg)
File "/root/krkn/krkn/run_kraken.py", line 218, in main
failed_post_scenarios = pod_scenarios.container_run(
File "/root/krkn/krkn/kraken/pod_scenarios/setup.py", line 92, in container_run
failed_post_scenarios = check_failed_containers(
File "/root/krkn/krkn/kraken/pod_scenarios/setup.py", line 199, in check_failed_containers
killed_container_list = killed_container_list.remove(item)
AttributeError: 'NoneType' object has no attribute 'remove'
`

from krkn.