Chore: Mobile: Add NoteBodyViewer tests

[personalizedrefrigerator]

Summary

This pull request allows testing code that includes communication with a WebView. At present, it includes tests for NoteBodyViewer.

Note

This pull request includes code from #10731 and a version #10748. As such, #10731 and #10748 should be reviewed and merged first.

Motivation

The goal of this pull request is to prevent regressions by increasing the code coverage of the mobile app.

This pull request was motivated, in particular, by these two issues:

• Mobile: cannot open previously opened note if navigating with links #10677
• Manual attachment downloading regression: https://discourse.joplinapp.org/t/android-app-doesnt-download-attachments-pictures/39090

Although this pull request currently only includes tests for NoteBodyViewer, it should allow writing tests for Note.tsx and additional tests for NoteEditor.tsx. It should also allow more complete testing of the plugin logic on mobile.

Changes made

• Mocks ExtendedWebview using JSDOM.
• Only uses jsdom for certain tests for code intended to run in a WebView, rather than for all tests. The JSDOM constructor doesn't seem to work in a jsdom environment (it fails with a TextEncoder is undefined error).
• Fixes warnings in seeveral other mobile tests.
• Adds sharp as a development dependency of app-mobile -- it's used by shim-init-node when attaching pictures to notes during testing.

Manual testing

Android 13:

• Started the app
• Opened the note viewer -- verified that markdown is still rendered.
• Opened the note editor -- verified that notes can still be edited.
• Opened settings -- verified that plugins still load.

[personalizedrefrigerator]

Currently, the virtual DOM for this mock is accessed with code similar to the following:

// Gets the <View></View> that is assigned a testID above:
const webviewContent = await screen.findByTestId('NoteBodyViewer');

// Get the `document` prop provided to the <View> through `additionalProps`:
const doc = webviewContent.props.document;

// Use the `document`
expect(doc.querySelector('h1').textContent).toBe('something'));

Above, document is retrieved through the props passed to the <View> object.

Previously, I was trying to access document through the ref passed to the parent of the ExtendedWebView. This, however, 1) seems to involve tree navigation and 2) (await screen.findByTestId('id')).parent.props.ref does not seem to contain the ref forwarded to the WebView's parent.

[laurent22]

There is now a conflict on shim-init-react.ts