Log group config errors to the pod and refine logic

[DaoDaoNoCode]

Closes #463

Description

This PR mainly changes the error handle a little bit, to make the error more clear.

1. When the group is not set, or it's an empty string, show the error No group is set in the group config, please set one or more group. (May need wording)
2. When the group does not exist, show the error in the pod log (We only showed it in the dashboard notification center before)

How Has This Been Tested?

1. Change the group config in the dashboard config CR, change the adminGroups to a non-existed group like fake-group
2. Wait for 2 minutes (We need to wait until the backend fetches the latest cluster data)
3. Refresh the user management settings page, you should see 2 error messages in both pod logs and dashboard UI

• The group fake-group no longer exists in OpenShift and has been removed from the selected group list.
• No group is set in the group config, please set one or more group.

4. Refresh the page again, you should only see the second message
5. Try to set or unset the groups, and make sure nothing is broken

Test Impact

Add tests for useWatchGroups hook.

Request review criteria:

Self checklist (all need to be checked):

• The developer has manually tested the changes and verified that the changes work
• Commits have been squashed into descriptive, self-contained units of work (e.g. 'WIP' and 'Implements feedback' style messages have been removed)
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has added tests or explained why testing cannot be added (unit tests & storybook for related changes)

If you have UI changes:

• Included any necessary screenshots or gifs if it was a UI change.
• Included tags to the UX team if it was a UI/UX change (find relevant UX in the SMEs section).

After the PR is posted & before it merges:

• The developer has tested their solution on a cluster by using the image produced by the PR to main

[Gkrumbach07]

/lgtm

flow as described is accurate

[manaswinidas]

/lgtm

Tested. Works fine.

[christianvogt]

@DaoDaoNoCode please add tests

[christianvogt]

/lgtm
/approve

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: christianvogt, Gkrumbach07, manaswinidas

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