Service Account Key Creation: -o json produces invalid JSON #1527

Description

When running stackit service-account key create -e <sa-email> -o json the output is not pure JSON. Before the JSON output there is an extra line Created key for service account <sa-email> with ID "<some-id>".

Steps to reproduce

1. Run stackit service-account create -n mytest
2. Run stackit service-account key create -e <sa-email> -o json > sa.json
3. Run cat sa.json | jq. Observe an error
4. Inspect sa.json and see that it is not valid JSON

Actual behavior

The JSON output looks like this:

Created key for service account <sa-email> with ID "<some-id>"
{
  "active": true,
  "createdAt": "2026-08-07T14:03:18Z",
  ...

Expected behavior

I expect the output to be valid JSON:

{
  "active": true,
  "createdAt": "2026-08-07T14:03:18Z",
  ...

Environment

• OS: macOS 26.5.2
• Version of STACKIT CLI (see stackit --version): v0.70.0

Additional information

This is new behavior in one of the latest releases. I can't pinpoint the exact CLI version that introduced this behavior. A week or so ago I didn't observe this issue.