Fix issue with missing workspace's agent config

MR: Pending

Description

After we fixed the issue for /prerequisites API with missing agent config with issue, we would like to continue looking into the similar sentry error, and find root cause for it.

Sentry error - https://gitlab.slack.com/archives/C093VPLM53L/p1751397193364379

We would first need to understand why workspace agent has missing remote_development_agent_config first, and then bring up a proper solution for it. And finally make DB migrations for fixing existing data.

Acceptance criteria

• First understand why this happens & bring up proper fix accordingly

Implementation plan

TODO: Fill out or delete (optional)

[Provide a high-level plan for implementation of this issue, including relevant technical and/or design details.]