build(tsconfig): update storybook and playground tsconfig

[nickofthyme]

Summary

This PR fixes the build issue related to /tsx?/ files in ./.stroybook and ./.playground by adding these respective local directories to tsconfig.json includes.

With these changes, the files in these directories will now be enforced.

Checklist

• Each commit follows the convention

[codecov-io]

Codecov Report

Merging #377 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #377      +/-   ##
==========================================
+ Coverage   98.25%   98.27%   +0.02%     
==========================================
  Files          38       38              
  Lines        2801     2784      -17     
  Branches      661      657       -4     
==========================================
- Hits         2752     2736      -16     
  Misses         44       44              
+ Partials        5        4       -1

Impacted Files	Coverage Δ
src/specs/settings.tsx	94.44% <0%> (-0.13%)	⬇️
src/chart_types/xy_chart/store/chart_state.ts	97.6% <0%> (+0.14%)	⬆️

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[markov00]

LGTM!

[markov00]

🎉 This PR is included in version 12.0.2 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)

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