chore: Fix webpack version import warning

[hexaltation]

Context

The webpack build warns about incoming changes in package.json import.

WARNING in ./stubs/app/common/version.ts 2:23-42
Should not import the named export 'version' (imported as 'packageJson') from default-exporting module (only default export is available soon)
 @ ./app/client/ui/AppHeader.ts 5:0-46 51:29-44 51:50-67 51:89-106
 @ ./app/client/ui/errorPages.ts 3:0-52 90:25-34
 @ ./app/client/errorMain.ts 2:0-57 3:28-41

webpack 5.97.1 compiled with 1 warning in 4928 ms

This PR adresses this.

Proposed solution

I follow advice in the warning to change the way we import package.json.

Has this been tested?

• 👍 yes, locally
  Version still displays in the UI.