Enable CSS scroll snap code across more browsers

[nainar]

Safari/Firefox/Edge have scroll-snap enabled. Chrome now has it enabled starting 69.

This PR enables scroll snap code for all browsers/OSes.

Addresses: #16508

[codecov-io]

Codecov Report

Merging #17058 into master will decrease coverage by 1.37%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master   #17058      +/-   ##
==========================================
- Coverage   77.88%    76.5%   -1.38%     
==========================================
  Files         562      563       +1     
  Lines       41156    43863    +2707     
==========================================
+ Hits        32054    33558    +1504     
- Misses       9102    10305    +1203

Flag	Coverage Δ
#integration_tests	36.13% <ø> (-0.05%)	⬇️
#unit_tests	76.44% <0%> (-0.49%)	⬇️

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[cathyxz]

This change looks fine, but will probably require very extensive testing on all relevant devices / browsers to see if it breaks anything. Do you mind commenting with a checklist here (or just assigning the PR to me) after that's been done?

[nainar]

Tracking manual testing on the following platforms:

• iOS + Safari
• iOS + Chrome
• iOS + Firefox
• iOS + Edge
• Android + Opera
• Android + Chrome
• Android + Firefox
• Android + Edge

[nainar]

Logging offline discussion:

Turning this into an experiment with following movement:

• 2 weeks: 1% canary
• 2 weeks: 10% prod
• 2 weeks: 50% prod
• 4 weeks: 100% prod
• TURN ON FULL! 🎆

@cathyxz take a look?

[cathyxz]

I think we made a new rule banning creating experiments and flipping flags in the same PR. It makes for easier reverts.

[cathyxz]

LGTM, just move the flag flip to a different PR.

[nainar]

@cathyxz - Split up the canary-config change into it's own PR.