Fix Unicode 1.1 emojis

What does this MR do?

• Adjust font-stack on emojis to only use font-family: "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";

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

Why was this MR needed?

When using the full font-stack some the Unicode 1.1 emojis are taken up by fonts closer up the stack and don't represent the emoji well.

font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";

• On Windows, "Segoe UI" -> "Arial" takes over
• On mac OS, "Helvetia" -> ".SF NS Display" takes over

mac OS 10.12.3	Windows 10

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When using a shorter emoji font-stack, everything seems to be covered well

font-family: "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";

• On Windows, "Segoe UI Emoji" takes over
• On mac OS, "Apply Color Emoji" takes over

mac OS 10.12.3	Windows 10

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Screenshots from Emoji Unicode by Version demo, https://jsfiddle.net/MadLittleMods/xw9moyfw/

@MadLittleMods, https://gitlab.com/gitlab-org/gitlab-ce/issues/29557#note_25544684

Does this MR meet the acceptance criteria?

• Tests
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #29557 (closed)

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cc @lbennett