[daniele-verducci]

In #17921 I didn't realize that navigating to a parent folder triggers an onBack event (!!), so introduced a bug that caused the screen to close when trying to navigate to a folder that can't be accessed.
This fixes that bug, makes code more readable and adds a documentation comment.

🏁 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)

[github-actions]

📱 QA build

Download	app-qa-debug.apk
QR code	Open the QR code for this download
Commit	7f8c416
Version	17937
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]

master-IT test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/17937-IT-master-16-49

[github-actions]

stable22-IT test failed: https://www.kaminsky.me/nc-dev/android-integrationTests/17937-IT-stable22-16-52

[github-actions]

SpotBugs

Category	Base	New
Bad practice	24	24
Correctness	45	45
Dodgy code	146	146
Experimental	1	1
Malicious code vulnerability	1	1
Multithreaded correctness	13	13
Performance	28	28
Security	15	15
Total	273	273

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...wncloud/android/ui/activity/UploadFilesActivity.kt	0.00%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!