JS module loading for older Androids (fixes #9311)

[nihil-admirari]

Purpose / Description

JS modules must have text/javascript MIME, otherwise they won't load: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules.

Fixes

Fixes #9311.

Approach

guessMimeType() works on Android 10+. MIME type must be set explicitly on older Androids.

How Has This Been Tested?

Android 8.0 and 13.0 in emulator.

Checklist

Please, go through these checks before submitting the PR.

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[welcome]

First PR! 🚀 We sincerely appreciate that you have taken the time to propose a change to AnkiDroid! Please have patience with us as we are all volunteers - we will get to this as soon as possible.

[david-allison]

This needs to be checked against #10175 before it goes in.

See: f758778

[nihil-admirari]

I've restored ba41619 implementation with the exception of JS MIME type, which should be text/javascript.

I wasn't able to reproduce #10175. I have certain questions about that issue, however, which I've listed in #10175 (comment).

[nihil-admirari]

@david-allison, it's been a week since I've pushed the last changes, can you please take a look?

Considering that you've been unable to reproduce #10175 yourself, and that @Anthropos888 still got the issue even in a release with module loading changes removed, these changes are probably safe to merge.

[mikehardy]

this seems reasonable and is backed by testing, it does seem safe to me