fix: add pull secret for fbc preview index image

[jinqi7]

Since the create-pyxis-image will be added in FBC pipeline, we need to add the pull secret for fbc preview index.

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[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[happybhati]

❗Promoted to staging ❗