Fix keyboard accessibility after creating a wallet

[lukaw3d]

• Fixes Buttons aren't focusable by keyboard after user creates wallet #863
• Makes code around Layers more consistent: escape to close, override background color, and explicitly uses modal everywhere

[github-actions]

MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ EDITORCONFIG	editorconfig-checker	7		0	0.02s
✅ GIT	git_diff	yes		no	0.01s
✅ TSX	eslint	6	0	0	5.18s

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Set VALIDATE_ALL_CODEBASE: true in mega-linter.yml to validate all sources, not only the diff

[codecov]

Codecov Report

Merging #864 (4eb371e) into master (05cd709) will decrease coverage by 0.05%.
The diff coverage is 40.00%.

@@            Coverage Diff             @@
##           master     #864      +/-   ##
==========================================
- Coverage   88.07%   88.01%   -0.06%     
==========================================
  Files         102      102              
  Lines        1643     1644       +1     
  Branches      340      340              
==========================================
  Hits         1447     1447              
- Misses        196      197       +1     

Flag	Coverage Δ
cypress	58.00% <40.00%> (-0.04%)	⬇️
jest	74.93% <0.00%> (-0.05%)	⬇️

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Impacted Files	Coverage Δ
src/app/components/FatalErrorHandler/index.tsx	71.42% <ø> (ø)
src/app/components/Modal/index.tsx	80.00% <ø> (ø)
src/app/components/TransactionModal/index.tsx	91.66% <ø> (ø)
...pages/OpenWalletPage/Features/FromLedger/index.tsx	68.42% <ø> (ø)
src/app/pages/CreateWalletPage/index.tsx	90.90% <25.00%> (-2.85%)	⬇️
src/app/pages/AccountPage/index.tsx	97.43% <100.00%> (ø)

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