Add AnnouncementBanner tests; Fix defaultState location

[imnasnainaec]

Completes the reorg of #3054
A small piece of #3180

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This change is 

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.76%. Comparing base (f90b698) to head (060dd24).
Report is 19 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3311      +/-   ##
==========================================
+ Coverage   74.58%   74.76%   +0.17%     
==========================================
  Files         279      278       -1     
  Lines       10710    10710              
  Branches     1291     1291              
==========================================
+ Hits         7988     8007      +19     
+ Misses       2358     2339      -19     
  Partials      364      364              

Flag	Coverage Δ
backend	83.89% <ø> (+0.08%)	⬆️
frontend	66.77% <100.00%> (+0.26%)	⬆️

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[jasonleenaylor]

src/components/AnnouncementBanner/tests/index.test.tsx line 39 at r2 (raw file):

    await renderAnnouncementBanner();
    expect(
      screen.queryByLabelText(AnnouncementBannerTextId.ButtonClose)

Add a comment about why we are using the ButtonClose

[jasonleenaylor]

Reviewed 20 of 25 files at r1, 5 of 5 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)

[jasonleenaylor]

Reviewed 2 of 2 files at r3, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)

[jasonleenaylor]

Reviewed 2 of 2 files at r4, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)