feat: Return entity metadata in delete REST API response

[albinsuresh]

Proposed changes

Fixes:

• Entity store DELETE API to return full entity metadata of deleted entities
• Return HTTP 204 when deleting non-existent entity

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (general improvements like code refactoring that doesn't explicitly fix a bug or add any new functionality)
• Documentation Update (if none of the other choices apply)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Paste Link to the issue

• entity api should return full entity objects of deleted entities #3385
• entity api should return HTTP 204 status code and no body when entity does not exist #3387

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA (in all commits with git commit -s)
• I ran cargo fmt as mentioned in CODING_GUIDELINES
• I used cargo clippy as mentioned in CODING_GUIDELINES
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

[codecov]

Codecov Report

Attention: Patch coverage is 86.11111% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/common/mqtt_channel/src/topics.rs	0.00%	3 Missing ⚠️
...ates/core/tedge_agent/src/entity_manager/server.rs	75.00%	1 Missing ⚠️
crates/core/tedge_api/src/entity_store.rs	90.90%	1 Missing ⚠️

Additional details and impacted files

📢 Thoughts on this report? Let us know!

[github-actions]

Robot Results

✅ Passed	❌ Failed	⏭️ Skipped	Total	Pass %	⏱️ Duration
585	0	3	585	100	1h31m31.570279999s

[didier-wenzek]

Approved

[didier-wenzek]

I confirm my approval

[reubenmiller]

Approved