Incompatible file breaks the UI when uploaded

[IsaSih]

Setup
Rancher v2.12-49289cc9c6590b361d64950977dd20b1214908d7-head
Dashboard master 28636c1
Rancher CLI v2.11.0-rc.1

• Rancher UI Extensions: Harvester UI extension

Describe the bug
Incompatible file breaks the UI when imported

To Reproduce
1- Create an rke2 cluster (via Clusters Management or main page - any provider)
2- Scroll the Create cluster page down, under Cluster Configuration select Cluster Configuration
3- Click Read from file and import a png or jpeg file
4- Observe how the UI becomes non-responsive

Result
The incompatible file extension breaks the UI, by making it non-responsive and then the file content loads as in the screen recording:

Screen.Recording.2025-05-06.at.10.10.09.mov

Expected Result
The UI could prevent incompatible file extensions from being uploaded (like non-character files)