chore: switch catalog-index tag to next for main branch

[christoph-jerolimov]

Description

see https://quay.io/repository/rhdh/plugin-catalog-index?tab=tags / https://redhat-internal.slack.com/archives/C04CUSD4JSG/p1769602536390409?thread_ts=1769501176.736749&cid=C04CUSD4JSG

Which issue(s) does this PR fix

none

PR acceptance criteria

Please make sure that the following steps are complete:

• GitHub Actions are completed and successful
• Unit Tests are updated and passing
• E2E Tests are updated and passing
• Documentation is updated if necessary (requirement for new features)
• Add a screenshot if the change is UX/UI related

How to test changes / Special notes to the reviewer

[openshift-ci]

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Details

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

The image is available at:

• quay.io/rhdh-community/rhdh:pr-4087
• quay.io/rhdh-community/rhdh:pr-4087-4baa6f62