Resolve duplication between `_configuration_banner.html.haml` files

Description

There's a bit of duplication between:

• app/views/projects/services/prometheus/_configuration_banner.html.haml
• app/views/projects/settings/operations/_configuration_banner.html.haml

Implementation notes

Let's create a single shared _configuration_banner.html.haml partial which we can reuse where these are being used.

Context

The following discussion from !63257 (merged) should be addressed:

• @pslaughter started a discussion:

  issue (maintainability, non-blocking): There's a lot of duplication between these two _configuration_banner.html.haml files. Let's see if we can encapsulate them somehow.

  I'll create a follow-up for this 👀