[stable6] feat(FilePicker): Improve pick and navigation logic to match user expectation

[backportbot]

Backport of #2033

Warning, This backport's changes differ from the original and might be incomplete ⚠️

Todo

• Review and resolve any conflicts
• Amend HEAD commit to remove the line stating to skip CI

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.

[susnux]

(rebased for CI)

[codecov]

Codecov Report

❌ Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 42.96%. Comparing base (6ee3bd5) to head (34067ac).
⚠️ Report is 5 commits behind head on stable6.

Files with missing lines	Patch %	Lines
lib/filepicker-builder.ts	0.00%	10 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@## stable6 #2051 +/- ##
===========================================
- Coverage 43.53% 42.96% -0.57% 
===========================================
Files 22 22 Lines 758 768 +10 Branches 92 92 ===========================================
Hits 330 330 - Misses 427 437 +10 
Partials 1 1 

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