Replace gl-flex-wrap by gl-flex-wrap-wrap

What does this MR do?

BREAKING CHANGE: remove deprecated gl-[breakpoint?-]flex-wrap and gl-flex-nowrap. Instead use gl-[breakpoint?-]flex-wrap-wrap and gl-flex-wrap-nowrap.

The gl-flex-wrap class is deprecated in favor of gl-flex-wrap-wrap. This is more consistent with our name convention of gl-{breakpoint?}-{property}-{value}.

Closes #1951 (closed)

After the new major library version is adopted in gitlab-org/gitlab, a few snapshots will need to be updated.

Does this MR meet the acceptance criteria?

Conformity

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• GitLab UI's contributing guidelines.
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  • GitLab: 6 MR (look at related MRs in the issue to be closed)
  • CustomersDot: https://gitlab.com/gitlab-org/customers-gitlab-com/-/merge_requests/6968
  • Status Page: no needed
• Added the ~"component:*" label(s) if applicable.

Security

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Accessibility

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• All actions and functionality can be done with a keyboard.
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• Color combinations have sufficient contrast.