fix(device): improve battery charging status detection and robustness

[joshtrichards]

Mostly a refactor (code modernization and readability), but also:

• improved charge status logic (uses both EXTRA_STATUS and EXTRA_PLUGGED)
• adds logging for diagnostics
• doc/comment improvements

The charge status logic prevents false positives for "charging," such as when the device is plugged in but not actually charging and also handles weird devices and status results as robustly as possible.

• Tests written, or not not needed

[github-actions]

Codacy

SpotBugs

Category	Base	New
Bad practice	42	42
Correctness	74	74
Dodgy code	257	257
Experimental	1	1
Internationalization	7	7
Malicious code vulnerability	2	2
Multithreaded correctness	34	34
Performance	43	43
Security	18	18
Total	478	478

[github-actions]

blue-Light-Screenshot test failed, but no output was generated. Maybe a preliminary stage failed.

[github-actions]

test-Unit test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/16450-Unit-test-19-54

[github-actions]

APK file: https://www.kaminsky.me/nc-dev/android-artifacts/16450.apk



To test this change/fix you can simply download above APK file and install and test it in parallel to your existing Nextcloud app.

[alperozturk96]

Hi! Thanks for your contribution.

This PR has been in draft for some time, so we'd like to check whether you're still planning to work on it.

If the PR is still valid and you intend to continue, please mark it as Ready for Review (remove the draft status) and add the review label. We'll then be happy to take a look.

If you no longer plan to continue with this PR, please let us know so we can keep the backlog up to date.

Thanks!