bug(build): Linux flatpak commands fail on Arch Linux

[Hoverth]

Current Behavior:

flatpak-builder returns:

Dependency Sdk: org.freedesktop.Sdk 23.08
Installing org.freedesktop.Sdk/x86_64/23.08 from flathub
error: No remote refs found for ‘flathub’
Error installing deps: running `flatpak --user install -y --noninteractive flathub org.freedesktop.Sdk/x86_64/23.08`: Child process exited with code 1

after running flatpak install flathub org.freedesktop.Sdk//23.08 (seems like it doesn't like the x86_64):

Downloading sources
hint: Using 'master' as the name for the initial branch. This default branch 
hint: is subject to change. To configure the initial branch name to use in all 
hint: of your new repositories, which will suppress this warning, call:
[...]
hint:   git branch -m <name> 
Initialized empty Git repository in /[...]/verso/.flatpak-builder/git/https_github.com_servo_servo-U7K5T2/ 
Fetching full git repo https://github.com/servo/servo
error: RPC failed; HTTP 400 curl 92 HTTP/2 stream 7 was not closed cleanly: CANCEL (err 8) 
fatal: expected 'packfile' 
Failed to download sources: module verso: Child process exited with code 128

After increasing the git http post buffer by running git config --global http.postBuffer 157286400, it runs fine until it needs the org.freedesktop.Sdk.Extension.rust-stable/x86_64/23.08 extension, where it fails.

After installing both needed extensions (rust-stable and llvm18), and re-running it, it builds.

Steps To Reproduce:

Try to build on an install of Arch Linux with KDE done via the archinstall tool

Environment:

• OS: Arch Linux (x86_64)
• Flatpak: 1.15.10
• Flatpak-Builder: 1.4.4

[wusyong]

I guess we should revert #143