Fallback in case SULocalizedStringFromTableInBundle() fails

[zorgiepoo]

SULocalizedStringFromTableInBundle() should only fail in the abnormal situation where the app bundle may have been moved while it was running. Technically the app is running in an unsupported state but I suppose we can guard against it here.

This is a continuation of #2527 and fixes #2524

Misc Checklist

• My change requires a documentation update on Sparkle's website repository
• My change requires changes to generate_appcast, generate_keys, or sign_update

Testing

I tested and verified my change by using one or multiple of these methods:

• Sparkle Test App
• Unit Tests
• My own app
• Other (please specify)

Tested test app works and works with another language still.

macOS version tested: 14.4 (23E214)