Updates chart guidance

What does this MR do?

Reverses the guidance on creating new charts in GitLab UI.

Previously we recommended creating a new component for every type of chart created, but this is getting unwieldy and creating issues for engineering with the more complex charts introduced. Creating 10x more engineering work for single-use charts.

It's imperative that any charts created continue to follow the Pajamas design guidelines to ensure consistent rendering across GitLab.

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines.
• GitLab UI's contributing guidlines.
• If it changes a Pajamas-compliant component's look & feel, the MR has been reviewed by a UX designer.
• If it changes GitLab UI's documentation guidelines, the MR has been reviewed by a Technical Writer.
• If the MR changes a component's API, integration MR(s) have been opened in the following projects to ensure that the @gitlab/ui package can be upgraded quickly after the changes are released:
  • GitLab: mr_url
  • CustomersDot: mr_url
  • Status Page: mr_url
• Added the ~"component:*" label(s) if applicable.