Bump OUI dependency to 1.2.0 cherry-pick

[lezzago]

Description

Cherry pick of #4170

Issues Resolved

N/A

Testing the changes

Manual local testing

Check List

• All tests pass
  • yarn test:jest
  • yarn test:jest_integration
  • yarn test:ftr
• New functionality includes testing.
• New functionality has been documented.
• Update CHANGELOG.md
• Commits are signed per the DCO using --signoff

[ohltyler]

If this is only needed to ensure testing in a test cluster, can we have this pointed to a different test branch? I'm afraid of merging this change in here can lead to complications when merging back into main/2.x if the source PR isn't merged yet, or has changes that could cause conflicts

[codecov]

Codecov Report

Merging #4337 (ecd7a0e) into feature/feature-anywhere (12b6d44) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@                     Coverage Diff                      @@
##           feature/feature-anywhere    #4337      +/-   ##
============================================================
- Coverage                     66.36%   66.36%   -0.01%     
============================================================
  Files                          3271     3271              
  Lines                         62997    62996       -1     
  Branches                       9758     9757       -1     
============================================================
- Hits                          41811    41809       -2     
- Misses                        18840    18841       +1     
  Partials                       2346     2346              

Flag	Coverage Δ
Linux	66.31% <100.00%> (-0.01%)	⬇️
Windows	66.31% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/core/public/chrome/ui/header/header.tsx	73.33% <100.00%> (ø)
...ore/public/chrome/ui/header/header_breadcrumbs.tsx	100.00% <100.00%> (+10.00%)	⬆️

... and 1 file with indirect coverage changes

[joshuarrrr]

Approving so you have the option of merging if necessary. I plan to cut a 1.1.1 release of OUI that is limited to the icon change so that it will definitely be available.