Fix allowing user to change email

[johnthagen]

Closes #951

Also:

• Update signature of getCurrentUser() to return undefined to match style guide

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This change is 

[codecov-io]

Codecov Report

Merging #959 (e4b664a) into master (c8dcb13) will not change coverage.
The diff coverage is 40.00%.

@@           Coverage Diff           @@
##           master     #959   +/-   ##
=======================================
  Coverage   49.83%   49.83%           
=======================================
  Files         230      230           
  Lines        6486     6486           
  Branches      403      403           
=======================================
  Hits         3232     3232           
  Misses       2953     2953           
  Partials      301      301           

Flag	Coverage Δ
backend	55.47% <ø> (ø)
frontend	43.79% <40.00%> (ø)

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

Impacted Files	Coverage Δ
src/backend/localStorage.tsx	61.90% <0.00%> (ø)
src/components/UserSettings/UserSettings.tsx	0.00% <0.00%> (ø)
src/components/Login/AuthHeaders.tsx	75.00% <100.00%> (ø)
src/components/Login/LoginActions.tsx	58.49% <100.00%> (ø)

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[jasonleenaylor]

Reviewed 7 of 8 files at r1, 1 of 1 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)