[FL-3000] File browser: Empty folder label

[nminaylov]

What's new

• Showing <Empty> label in file browser if folder is empty

Verification

• Pull out SD card, run Applications app

Checklist (For Reviewer)

• [ ] PR has description of feature/bug or link to Confluence/Jira task
• [ ] Description contains actions to verify feature/bugfix
• [ ] I've built this code, uploaded it to the device and verified feature/bugfix

[github-actions[bot]]

PVS-Studio report for commit 55d3144d:

• Report

[github-actions[bot]]

Compiled firmware for commit a9d24850:

• 📦 Update package
• 📥 DFU file
• ☁️ Web/App updater