Task: Reinforce API Server Fetch

[n3rdc4ptn]

Understand the Task

Description
We need to reinforce the fetchApiServer method in https://github.com/openmcp-project/ui-frontend/blob/00d740e8339d9c5706c64a60b4b22055dc95e6ed/src/lib/api/fetch.ts#L54C5-L59C17.

Currently we optimistically parse to json. As sometimes the API server could answer with just text (plain/text) we should check the Content-Type before we parse the body.

We also need to proper handle occurring errors in that spot. So a well written try/catch is needed.

Any further valuable resources.

1. MCPs without flux installed,
2. answer on the flux endpoints with text 404 page not found.
   Preferred: lets use defensive try-catch block for JSON and use text alternatively

Optional: The Content-Type header in the response is: content-type: text/plain; charset=utf-8

What is required to accept the Task as done.

Done Criteria

• Catch possible errors, when parsing and handle them
• Check Content-Type before we parse it.
• parse Content accordingly (application/json, text/plain, ....)
• in the component where error is shown we no longer see JSon parsing issues