fix(typography): add missing eds-font-size-20

[booc0mtaco]

Summary:

• this size was referenced in code, but not defined as a token or variable.
• add it in after cross-checking with the related design
• Verify the sizing logic (1rem = 16px/16px) for font-size 20px

Test Plan:

• Wrote automated tests
• CI tests / new tests are not applicable
• Manually tested my changes, but I want to keep the details secret
• Manually tested my changes, and here are the details:
  • verify breakpoint appears properly
  • verify the token and css variable is defined

[booc0mtaco]

[github-actions]

size-limit report 📦

Path	Size
components	118.9 KB (0%)
styles	3.13 KB (+0.16% 🔺)

[codecov]

Codecov Report

Merging #1591 (d29374a) into next (fcef92f) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             next    #1591   +/-   ##
=======================================
  Coverage   91.70%   91.70%           
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  Files         279      279           
  Lines        4292     4292           
  Branches      784      784           
=======================================
  Hits         3936     3936           
  Misses        354      354           
  Partials        2        2           

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[jinlee93]

Weird those snaps were affected but the font size changes makes sense

[booc0mtaco]

@jinlee93 turns out those snaps had bugs in them 🐛. at full viewport, the percentage signs and the "/ XX" were supposed to be smaller. Those snaps were using the preset-003 which had the missing font size at that breakpoint. So this fixes that too :)

[booc0mtaco]