fix(baseline): update icons, add text to feedback link

[LeoMcA]

Summary

updates icons to subtly different colours

adds text to feedback link to make more visible

address review from prior PR:
#10128 (review)

• configure svgo to automatically remove height/width and add viewbox,
  and do so on baseline icons
• use classes instead of first/last-child for links
• don't show copy if low_date is undefined (it should always be defined
  if baseline is low/high, but just in case)

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Screenshots

Showing images alternating between new and old to show differences better:

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How did you test this change?

Loaded each variant locally, https://developer.mozilla.org/en-US/build.json shows pages for each status.

[github-actions]

This pull request has merge conflicts that must be resolved before it can be merged.

[OnkarRuikar]

"Newly available" and "Widely available" badges are not consistent with each other. Can we make "Widely available" same as the other:

[LeoMcA]

"Newly available" and "Widely available" badges are not consistent with each other.

This is, at least for now, intentional, as the widely available badge doesn't have a year attached, so the "widely available" text lives at the same level as the year in the information hierarchy, with "newly available" more of a qualifier, like so:

• Widely available
• 2021 (Newly available)
• 2022 (Newly available)
• 2023 (Newly available)
• Limited availability

Though of course, the intent here is to meet developers expectations, so thanks for your feedback - we'll take it on board, and make sure to fill out the survey (if you haven't already) to leave more feedback.

[caugner]

LGTM, just one consistency nit.