Addon-contexts improvements: bug-fixing, testing, typing

[leoyli]

Issue: #6559

What I did

• [bug-fix] when a param in a context carrying props = null, it mistakenly disable the context.
• [test] add 4 unit testing files to cover the most important logic of this addon (API related).
• [type] improve typing and its maintainability (separate type and implementation but collocate them, greatly inspired by @apastuhov, thanks!).
• [doc] fix typos in code comments, and remove the old NPM badge in README (migration leftovers).
• [build] strip-out type comments in the build.

How to test

• Running Jest (CI/CD should automate this).
• Look into Addon|Contexts stories in the official storybook (should not break the stories).

---

UPDATE:

• I have attached the above shortcut link and verify it did not break the addon stories.

[vercel]

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Latest deployment for this branch: https://monorepo-git-add-addon-contexts-tests.storybook.now.sh

[leoyli]

@shilman... the automation bot seems a bit crazy here... Did I do something wrong or you think it could be a bug 😢...

[codecov]

Codecov Report

Merging #6572 into next will increase coverage by 0.49%.
The diff coverage is 41.66%.

@@           Coverage Diff            @@
##            next   #6572      +/-   ##
========================================
+ Coverage   40.1%   40.6%   +0.49%     
========================================
  Files        633     633              
  Lines       8660    8660              
  Branches     619     620       +1     
========================================
+ Hits        3473    3516      +43     
+ Misses      5098    5055      -43     
  Partials      89      89

Impacted Files	Coverage Δ
addons/contexts/src/preview/libs/decorators.ts	100% <ø> (ø)
addons/contexts/src/preview/index.ts	0% <ø> (ø)	⬆️
addons/contexts/src/manager/libs/useChannel.ts	0% <ø> (ø)	⬆️
...ddons/contexts/src/preview/libs/getContextNodes.ts	92.3% <ø> (+92.3%)	⬆️
addons/contexts/src/preview/frameworks/react.ts	0% <0%> (ø)	⬆️
addons/contexts/src/manager/ToolBarMenuOptions.tsx	0% <0%> (ø)	⬆️
addons/contexts/src/manager/ToolbarControl.tsx	0% <0%> (ø)	⬆️
addons/contexts/src/preview/frameworks/vue.ts	0% <0%> (ø)	⬆️
addons/contexts/src/manager/AddonManager.tsx	0% <0%> (ø)	⬆️
addons/contexts/src/manager/ToolBarMenu.tsx	0% <0%> (ø)	⬆️
... and 10 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[codecov]

Codecov Report

Merging #6572 into next will increase coverage by 0.5%.
The diff coverage is 44%.

@@           Coverage Diff            @@
##            next    #6572     +/-   ##
========================================
+ Coverage   40.1%   40.61%   +0.5%     
========================================
  Files        633      633             
  Lines       8660     8660             
  Branches     619      620      +1     
========================================
+ Hits        3473     3517     +44     
+ Misses      5098     5054     -44     
  Partials      89       89

Impacted Files	Coverage Δ
addons/contexts/src/preview/libs/decorators.ts	100% <ø> (ø)
addons/contexts/src/preview/index.ts	0% <ø> (ø)	⬆️
addons/contexts/src/manager/libs/useChannel.ts	0% <ø> (ø)	⬆️
addons/contexts/src/preview/frameworks/react.ts	0% <0%> (ø)	⬆️
addons/contexts/src/manager/ToolBarMenuOptions.tsx	0% <0%> (ø)	⬆️
addons/contexts/src/manager/ToolbarControl.tsx	0% <0%> (ø)	⬆️
addons/contexts/src/preview/frameworks/vue.ts	0% <0%> (ø)	⬆️
addons/contexts/src/manager/AddonManager.tsx	0% <0%> (ø)	⬆️
addons/contexts/src/manager/ToolBarMenu.tsx	0% <0%> (ø)	⬆️
addons/contexts/src/manager/ToolBar.tsx	0% <0%> (ø)	⬆️
... and 10 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 74582af...8caf900. Read the comment docs.

[shilman]

@leoyli It's because you tagged this typescript--I don't think this is really a typescript issue per se, so I removed it.