Implemented tests for encrypted folders

[daniele-verducci]

Tests for encrypted (sub)folders.
Related: #17608

⚠️ The encrypted subfolders-related tests are supposed to fail in this one, until #17608 is merged

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not needed
• 🔙 Backport requests are created or not needed: /backport to stable-xx.x
• 📅 Milestone is set
• 🌸 PR title is meaningful (if it should be in the changelog: is it meaningful to users?)

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI (N/A)

[codecov]

Codecov Report

❌ Patch coverage is 61.72840% with 31 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...cloud/android/operations/e2e/E2EDeletionService.kt	30.00%	9 Missing and 5 partials ⚠️
...i/dialog/setupEncryption/EncryptionKeyGenerator.kt	77.19%	9 Missing and 4 partials ⚠️
...g/setupEncryption/SetupEncryptionDialogFragment.kt	0.00%	4 Missing ⚠️

📢 Thoughts on this report? Let us know!

[github-actions]

📱 QA build

Download	app-qa-debug.apk
QR code	Open the QR code for this download
Commit	7b34e22
Version	17697
Available until	7 days after this build

The QA build installs alongside a released Nextcloud app, so you can keep
using your existing install while testing.

Downloading the file requires a GitHub account, so open this link on the
device you want to test on, or transfer the APK to it.

[github-actions]

stable22-IT test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/17697-IT-stable22-15-26

[github-actions]

stable35-IT test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/17697-IT-stable35-15-31

[github-actions]

master-IT test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/17697-IT-master-15-34

[github-actions]

Codacy

SpotBugs

Category	Base	New
Bad practice	32	32
Correctness	58	58
Dodgy code	186	186
Experimental	1	1
Malicious code vulnerability	2	2
Multithreaded correctness	26	26
Performance	37	37
Security	18	18
Total	360	360

org.jetbrains.annotations.* is used. Please use androidx.annotation.* instead.