When repository not onboarded Read attachment throws error. Hiding link url in attachment.cds

[rashmiangadi11]

Describe your changes

This PR contains 2 fixes

1. When repository not onboarded Read attachment throws error. Hiding link url in attachment.cds
2. Nested entities throw error if the entity is defined with uppercase letters

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist before requesting a review

• I follow Java Development Guidelines for SAP
• I have tested the functionality on my cloud environment.
• I have provided sufficient automated/ unit tests for the code.
• I have increased or maintained the test coverage.
• I have ran integration tests on my cloud environment.
• I have validated blackduck portal for any vulnerability after my commit.

Upload Screenshots/lists of the scenarios tested

ST : https://github.com/cap-java/sdm/actions/runs/21632948587
MT : https://github.com/cap-java/sdm/actions/runs/21632961712

Scenarios tested

1. Tested nested entities with chapters entity defined using mix of uppercase and lowercase letters "cHapters"