Get rid of imagePullSecrets field in RHOAI deployment

[DaoDaoNoCode]

JIRA: RHOAIENG-10782

Description

This field was probably an old value and could be removed not to avoid the warnings.

How Has This Been Tested?

1. Get a 4.15+ OpenShift cluster
2. Install RHOAI operator on it and create the DSC
3. Check the warning events on the cluster, you should be able to see Unable to retrieve some image pull secrets (addon-managed-odh-pullsecret);
4. Go to DSC, edit dashboard entry to

dashboard:
  devFlags:
    manifests:
      - contextDir: manifests
        sourcePath: ''
        uri: 'https://github.com/DaoDaoNoCode/odh-dashboard/tarball/jira-rhoaieng-10782'

5. The deployment will start to rollout
6. Make sure there is no warning event above
7. Make sure the dashboard can still running normally

Test Impact

N/A, manifest change.

Request review criteria:

Self checklist (all need to be checked):

• The developer has manually tested the changes and verified that the changes work
• 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 or cypress tests 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.

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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.49%. Comparing base (a3f9ef8) to head (8283fa3).
Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3230      +/-   ##
==========================================
+ Coverage   85.47%   85.49%   +0.01%     
==========================================
  Files        1279     1280       +1     
  Lines       28161    28190      +29     
  Branches     7525     7535      +10     
==========================================
+ Hits        24071    24101      +30     
+ Misses       4090     4089       -1     

see 9 files with indirect coverage changes

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[DaoDaoNoCode]

Verified on managed cluster.

Before:

After:

No warnings

And I can access the dashboard normally. (Not sure why it's Open Data Hub, maybe it's because I changed the manifest directly? 🤔 )

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: andrewballantyne

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