image pull issue for some images which are injected on runtime in On-premise Air-gapped Environment

[Rajpratik71]

** BUG REPORT **

What happened:

Image pull issue for some images like 'docker.io/portworx/px-enterpri​se:2.7.4', 'quay.io/prometheus/alertmanager:v0.21.0' 'quay.io/prometheus/prometheus' and 'grafana/grafana:5.3.3' even after configuring "customRegistryURL" , image location are not getting overridden which are injected on runtime in airgapped environment.

What you expected to happen:

Image location should be overridden after configuring "customRegistryURL".

How to reproduce it (as minimally and precisely as possible):

In Helm 'values.yaml' , mention value of "customRegistryURL".

Anything else we need to know?:

Environment:

• Container Orchestrator and version: containerd v1.3.9

• Cloud provider or hardware configuration: On-premise Air-gapped Environment

• OS (e.g. from /etc/os-release):

`
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"
`

• Kernel (e.g. uname -a):
  Linux xxx-worker-rgu00u.xxx 3.10.0-1160.31.1.el7.x86_64 #1 SMP Thu Jun 10 13:32:12 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

• Install tools: Installed Portworx through Helm

• Others: