Plugin manager freezes with no output while installing plugins

[fuzyll]

Version and Platform (required):

• Binary Ninja Version: 5.4.10225-dev
• Edition: Ultimate
• OS: macOS
• OS Version: 26.5.2
• CPU Architecture: aarch64

Bug Description:
If you install a plugin, you'll see the following in the log (assuming you have it up):

...and then Binary Ninja will freeze until the process completes. If this takes awhile (because it's installing native stuff, or taking a long time to download, or whatever), you will have no idea whether it's working or stuck.

Steps To Reproduce:

1. Go into the Extension Manager
2. Install something like Sidekick that has a lot of dependencies
3. Wait

Expected Behavior:
If I were doing this in a terminal, I'd have some idea of what was going on through output from pip. We should probably capture that and display it?

Even just a little modal that says "Installing dependencies..." would possibly be better?

[fuzyll]

Builds >= 5.4.10335-dev will now show a modal like this with output:

If it fails, the modal will stick around and let you copy stuff. If it succeeds, it'll just go away.