FIX keybindings were pointing to null events

[Jessica-Koch]

Issue:

What I did

Some of the storybook keybindings were mapped to mistyped shortcuts, I fixed the incorrect mapping and also passed additonal keyboard event properties in the event object that I will need.

How to test

• Is this testable with Jest or Chromatic screenshots?
• Does this need a new example in the kitchen sink apps?
• Does this need an update to the documentation?

If your answer is yes to any of these, please make sure to include it in your PR.

[codecov]

Codecov Report

Merging #5375 into next will increase coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##             next    #5375      +/-   ##
==========================================
+ Coverage   30.37%   30.38%   +<.01%     
==========================================
  Files         622      621       -1     
  Lines        8957     8956       -1     
  Branches     1229     1229              
==========================================
  Hits         2721     2721              
+ Misses       5579     5578       -1     
  Partials      657      657

Impacted Files	Coverage Δ
lib/ui/src/settings/shortcuts.js	95.83% <ø> (ø)	⬆️
lib/ui/src/core/shortcuts.js	19% <ø> (ø)	⬆️
lib/ui/src/containers/nav.js	11.76% <ø> (ø)	⬆️
lib/core/src/client/preview/start.js	72.61% <0%> (ø)	⬆️
lib/theming/src/themes/light-syntax.ts

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[tmeasday]

LGTM

[storybook-safe-bot]

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🚫	PR is not labeled with one of: ["cleanup","doc-dependencies:update","BREAKING CHANGE","feature request","bug","documentation","maintenance","dependencies:update","dependencies","other"]

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