MR pipelines tab has error "Pipeline creation failed. Please try again." when there is no MR pipeline

Summary

When viewing the Pipelines tab of a Merge Request, the error message "Pipeline creation failed. Please try again." is displayed even when no MR pipeline is configured — but a branch pipeline exists. This is misleading, as no pipeline creation was actually attempted or failed.

Steps to Reproduce

1. Create a CI configuration that explicitly excludes merge_request_event as a pipeline source, e.g.:

test:
  script: exit 0
  rules:
    - if: '$CI_PIPELINE_SOURCE != "merge_request_event"'

2. Create a Merge Request for a branch using this configuration.
3. Navigate to the Pipelines tab of the MR.

Expected Behavior

The Pipelines tab should indicate that no MR pipeline is configured, without displaying an error message implying a failure occurred.

Actual Behavior

The following error message is displayed:

Pipeline creation failed. Please try again.

This is incorrect — no pipeline creation was attempted. A branch pipeline exists and is running successfully.

furkanayhan/test-project!56