Resolve "Show the merged yaml when syntax is invalid"

What does this MR do and why?

Sometimes with an invalid Ci config, the API still can show the merged yaml but the merged yaml tab does not show it. That's because we assumed that with an invalid CI configuration, we never would receive the mergedYaml result. So this MR removes that filter and instead add that logic inside the merged yaml component: if the mergedYaml property is available on the response, then we show it, otherwise we show a generic error message that the current errors prevent us from showing the merged yaml tab.

Screenshots or screen recordings

Before	after

How to set up and validate locally

• Go to CI/CD => Editor
• Write an a valid configuration
• Make one typo (e.g. add an extra e in a stage name for example)
• Go to the merged yaml tab
• Notice that you see the merged yaml

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #377265 (closed)