Fix for missing schema registry URL in rest, c3 and ksql (see issue 1425)

[Schm1tz1]

Description

When deploying self-managed components, schema.registry.url is missing for rest, ksql and c3 properties even if ccloud_schema_registry_url is congihured and ccloud_schema_registry_enabled: true while for connect it does work.

This is a fix for this issue.

Fixes # 1425

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How Has This Been Tested?

Example deployment in hybrid CCloud setup with a customer.

Checklist:

• [x] Any variable/code changes have been validated to be backwards compatible (doesn't break upgrade)
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] If required, I have ensured the changes can be discovered by cp-ansible discovery codebase
• [x] My code follows the style guidelines of this project
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] Any dependent changes have been merged and published in downstream modules