Improve message in MR widget when pipeline has failed/canceled and all merge checks are disabled

🧩 Problem Statement

When all the merge checks are disabled, and the pipeline for a merge request fails or is canceled, users are shown a danger variant of merge button without any supporting messaging explaining the scenario clearly to users.

Image

🧾 Background

&5998 (closed)

Proposal

• Re-evaluate the use of danger variant.
• Add a modal with a message to communicate to users that the pipeline has failed or was canceled and merge in this situation could have consequences.