internal/ui: Safari and Firefox does not handle multiple files dropped correctly

[cowboymacke]

Ebitengine Version

v2.7.5

Operating System

• Windows
• macOS
• Linux
• FreeBSD
• OpenBSD
• Android
• iOS
• Nintendo Switch
• PlayStation 5
• Xbox
• Web Browsers

Go Version (go version)

go1.22.3 darwin/arm64

What steps will reproduce the problem?

Run examples/dropfile in safari or firefox
Select two or more files and drop onto the canvas.

What is the expected result?

Multiple files showing upp inside the canvas

What happens instead?

Only one of the file shows up

Screen.Recording.2024-07-18.at.09.24.04.mov

Anything else you feel useful to add?

No response

[hajimehoshi]

Thank you for reporting!

I've not 100% determined, but I would not backport the fix to the stable branch 2.7 since the fix would be a little tricky.