fix: Fix missing auth.providers config causing CI failures in release-1.3

[rm3l]

Description of the change

Fix missing auth.providers config causing app startup to fail in release-1.3

Existing or Associated Issue(s)

• Fixes issues seen in https://github.com/redhat-developer/rhdh-chart/actions/runs/13112079983/job/36578033682?pr=86 and https://github.com/redhat-developer/rhdh-chart/actions/runs/13111723456/job/36576912437?pr=80 while trying to backport a few fixes to 1.3
• Related to chore: update backstage chart to 2.1.0 #46

Additional Information

Checklist

• Chart version bumped in Chart.yaml according to semver.
• Variables are documented in the values.yaml and added to the README.md. The pre-commit utility can be used to generate the necessary content. Use pre-commit run -a to apply changes.
• JSON Schema template updated and re-generated the raw schema via pre-commit hook.
• List tests pass for Chart using the Chart Testing tool and the ct lint command.

[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