Add tooltip with jobs full name to pipelines graph

## What does this MR do?

This MR adds a tooltip to build items in the pipelines graph as some build names are truncated.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

Some job names that are truncated need to be fully identified to avoid confusion.

## Screenshots (if relevant)

[Latest screenies here!](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6403#note_16968703).

## Does this MR meet the acceptance criteria?

- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #22089

See merge request !6403