UI: On file upload, progress bar doesn't update until finished uploading

Summary

The progress bar on the file upload widgets does not update until the file is finished uploading.

Steps to reproduce

1. upload a file, big enough to see the issue
2. the progress bar will not move until the entire file is uploaded, then it will show full

Environment

OS: CachyOS x86_64 Kernel: Linux 7.1.6-1-cachyos Uptime: 18 hours, 29 mins Packages: 9 (flatpak), 1531 (pacman) Shell: fish 4.8.1 Display (LG Ultra HD): 2160x3840 @ 1.5x in 27", 60 Hz [External] Display (SAM75CB): 2560x1440 in 27", 360 Hz [External, HDR] * DE: KDE Plasma 6.7.4 WM: KWin (Wayland) CPU: AMD Ryzen 7 7800X3D (8) @ 5.05 GHz GPU 1: NVIDIA GeForce RTX 3080 Ti [Discrete] GPU 2: AMD Raphael [Integrated] Memory: 13.44 GiB / 61.88 GiB (22%) Disk (/): 775.52 GiB / 3.63 TiB (21%) - btrfs Canary Desktop 2026.606.140333, Web 2026.605.11941, Linux 7.1.6-1-cachyos (x64), Electron 41.2.2, Chrome 146.0.7680.188, Node 24.14.1, Locale en-US

Logs or screenshots

632545550-bf80d908-0a2f-4aa9-aca8-9e2b83bdfc08.webm