Fix: Ubuntu GitHub test action (#643)

The `ubuntu-latest` tag was changed to point to Ubuntu 24.04 and has
caused regressions. See
microsoft/playwright#34251 and
electron/electron#42510 for more details.
TL;DR: 
> The solution is to lift the restrictions that Ubuntu 24.04 implements
in the AppImages.
> ```
> sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
> ```

## Update
The command above fixed the `Process failed to launch` error, but
instead produced a `Timeout 30000ms exceeded` error. For now, setting
tests to run on ubuntu-22.04 as that seems to work at the moment.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

## Summary by CodeRabbit

- **Chores**
- Enhanced the automated testing workflow by updating the operating
system to Ubuntu 22.04, improving the reliability of our testing
process.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Baruch Odem <[email protected]>

.github/workflows/tests.yml

@@ -18,7 +18,7 @@ jobs:
       matrix:
         os:
           # - windows-latest
-          - ubuntu-latest
+          - ubuntu-22.04 # TODO: Use latest when https://github.com/electron/electron/issues/42510 is fixed
           # - macos-latest
 
     runs-on: ${{ matrix.os }}
@@ -38,7 +38,7 @@ jobs:
       # I ran into problems trying to run an electron window in ubuntu due to a missing graphics server.
       # That's why this special command for Ubuntu is here
       - run: xvfb-run --auto-servernum --server-args="-screen 0 1280x960x24" -- yarn test:e2e
-        if: matrix.os == 'ubuntu-latest'
+        if: startsWith(matrix.os, 'ubuntu')
 
       - run: yarn test:e2e
-        if: matrix.os != 'ubuntu-latest'
+        if: ${{ !startsWith(matrix.os, 'ubuntu') }}