litmus-agent helmchart hook-pre-install-job missing imagePullSecrets

[bingwei-hong-partior]

What happened:
When using litmus-agent helm chart, it is notice that litmus-agent hook-pre-install-job.yaml created job missing imagePullSecrets to allow using private repo

What you expected to happen:
There should be imagePullSecrets for the litmus-agent and the pre-install-job should be updated to use imagePullSecrets

Where can this issue be corrected? (optional)

1. hook-pre-install-job.yaml to add take in imagePullSecrets under spec section.
2. Introduce imagePullSecrets in value file
3. the default tag should be the chart version 3.10.0 instead of latest too?
   repository: litmuschaos.docker.scarf.sh/litmuschaos/litmus-helm-agent
   pullPolicy: Always
   tag: "latest"

How to reproduce it (as minimally and precisely as possible):
Run the litmus-agent helm chart with a private repository