Mobile: Resolves #9819: Allow note viewer to extend to the edge of the screen while pinch zooming

[personalizedrefrigerator]

Summary

Fixes #9819 by moving horizontal padding in the note editor from the outside of the webview to the inside.

Screenshots

Not zoomed in:

Zoomed in:

Testing plan

1. Create a note with the following text:

# Test

This is a test note that contains text.

## Testing...

**Testing...**

Math that overflows:

$$ e^{i\theta} = \cos \theta + i \sin \theta $$
and thus
$$ \cos (\alpha + \beta) + i \sin (\alpha + \beta) = e^{i(\alpha +\beta)} = e^{i \alpha} + e^{i \beta} = \cos \alpha + i \sin \alpha + \cos \beta + i \sin \beta $$

2. Verify that there is padding between the note and the edges of the screen
3. Zoom in
4. Verify that there is no padding between the zoomed content and the edge of the screen (as is the case in a web browser app).

This has been tested successfully on Android 7 and Android 12.

• To-do: Test on iOS (in progress)