[Electron] Stop handlers not executed when path contains space

[msujew]

Bug Description:

When closing a Theia window, the path of the currently opened html file is checked against Theia's index.html:

theia/packages/core/src/electron-main/theia-electron-window.ts

Line 125 in ede3d6f

const safeToClose = !currentUrl.includes(frontendUri) || await this.checkSafeToStop(reason);

However, if the current path contains a URL encodable character, this check fails, which results in OnWillStop handlers not being executed. Consequently, the user is never asked to confirm anything (unsaved editors, etc.) and the app simply closes.

Steps to Reproduce:

1. Built a Theia app and place it in a path with a space
2. Edit a file (disable auto save)
3. Exit the application. The app should close without confirmation

Additional Information

• Operating System: macOS, Windows
• Theia Version: 1.25.0