Description of problem:

Home page and learning path custom data gives 401, with a change in backstage 1.28 if proxy credentials are required

See Backstage 1.28 release notes about the BREAKING: Proxy backend plugin protected by default

https://github.com/backstage/backstage/releases/tag/v1.28.0 

Prerequisites (if any, like setup, operators/versions):

Steps to Reproduce

1. Setup custom data for home page , follow https://docs.redhat.com/en/documentation/red_hat_developer_hub/1.2/html/getting_started_with_red_hat_developer_hub/proc-customize-rhdh-homepage_rhdh-getting-started#proc-customize-rhdh-homepage_rhdh-getting-started 
2. Setup costom data for learning path, follow https://docs.redhat.com/en/documentation/red_hat_developer_hub/1.2/html/getting_started_with_red_hat_developer_hub/proc-customize-rhdh-learning-paths_rhdh-getting-started 

Actual results:

in browser network call can see api call for home and learning path fails with 401

Expected results:

API call for home and learning path should be successful 

Reproducibility (Always/Intermittent/Only Once): 

Always 

Build Details:

Works with 1.2.2 but is not working on showcase main tested on commit f17535c394aa558b6299a5c7dde7f819520142a8 

Additional info (Such as Logs, Screenshots, etc):