[BUG] No instance created on timeout

## Description
Calling the /execute endpoint for a workflow that takes long and if a timeout occurs, the instance is not created/visible in the editor.

## Steps to Reproduce
- Have a workflow that takes a lot of time to execute.
- Call the workflow and make sure that your http request will timeout after a few seconds.

3. **Attachments**:
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4. **Reproduction Rate**: Indicate how often the bug occurs when following these steps (e.g., "every time", "intermittently: about 50% of the time").
Always

5. **Video/Screenshots**: Sometimes, complex behaviors are better shown than described. If you think a video or screenshots would help clarify the issue, please include them.
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6. **Additional Configuration**:
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## Expected Behavior
- The instance should still be created/be visible in the editor. By visible I mean to have a record of that execution.

## Actual Behavior
- No new instance is created in the list.

## Environment
- **Elsa Package Version**: Specify the version. If you've cloned the repo, mention if you are using the latest source code from the main branch. - 3.1.1
- **Operating System**: Include your OS version (e.g., Windows 10, macOS Big Sur, Ubuntu 18.04). - Windows
- **Browser and Version**: If applicable, include your browser and version (e.g., Chrome 92). - Edge

Start by reproducing the timeout through the /execute endpoint with a long-running workflow, then trace how execution records are created and exposed in the editor. Done means the timed-out request still leaves a visible execution instance record in the editor.

Written by the indexing model from the issue text.