Adds `Buy Pipeline minutes` menu item to the the `User Menu`

What does this MR do and why?

Adds Buy pipeline minutes menu item to the user menu as well as the Yellow notification dot. The logic was "translated" to Vue from this haml

It is based on another MR that is about to be merged

How to set up and validate locally

1. Enable the feature flag:

echo "Feature.enable(:super_sidebar_nav)" | rails c

2. Enable the user setting from the user dropdown:

3. The super sidebar should now appear on every page.

4. It is difficult to simulate the environment for this case so given that the BE code was not changed and just provided to the frontend in a different place, we can apply the patch to see the frontend changes. You shoudl be running EE instance though

CI_mins.patch

Go to the gitlab folder of your gdk, move the CI_mins.patch there, and apply it running

git apply CI_mins.patch

5. Navigate to some project or group page e.g. http://localhost:3000/gitlab-org/gitlab-shell - this menu item is not displayed on pages that do not have CI Minutes context (e.g index or profile page)

6. You should see the Buy Pipeline Minutes with a clock icon and warning text as well as a yellow notification dot on the dropdown toggle. The Yellow dot is mutually exclusive with the yellow text in the menu item. Once the menu item is clicked - the dot disappears but the yellow text shows up. Because we have applied the patch where both are always ON you won't see this behavior.

Screenshots

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MR acceptance checklist

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Related to #390397 (closed)