fix: remove dead 0x0.st upload hint from error message

[0xdeadd]

Summary

• Remove the curl -F ... https://0x0.st hint from the error message since 0x0.st has disabled uploads
• Replace with a generic hint to view the log with cat for copying

0x0.st is currently returning "uploads disabled because it's been almost nothing but AI botnet spam." Users hitting an install error are then given a second broken command, which isn't a great experience.

If/when a replacement paste service is chosen, the hint can be updated to point there.

Ref #4396

Test plan

• Trigger an archinstall error and verify the updated hint text is shown

[svartkanin]

We shouldn't remove the hint to upload the file but rather find an alternative instead.
Most users are stuck in getting the log file extracted so we need clear guidance how to do that

[Softer]

Look at my #4511, maybe my solution is better?

[0xdeadd]

Closing this in favor of @Softer's #4511 — their --share-log implementation is the right approach (replaces the hint with a working alternative instead of just removing it). Thanks @svartkanin for the feedback that pointed in this direction.