Handle OAuth2 error in `handle_callback!/1`

[kevinam99]

Based on issue https://github.com/achedeuzot/ueberauth_auth0/issues/193. Saw that this issue has been technically resolved in the discussions but the fix hasn't been added yet so I thought of creating the PR.

Added this fix based on @benkimpel's comment https://github.com/achedeuzot/ueberauth_auth0/issues/193#issuecomment-984808643

Hope this is still relevant, though

[benkimpel]

Based on issue https://github.com/achedeuzot/ueberauth_auth0/issues/193. Saw that this issue has been technically resolved in the discussions but the fix hasn't been added yet so I thought of creating the PR.

Added this fix based on @benkimpel's comment https://github.com/achedeuzot/ueberauth_auth0/issues/193#issuecomment-984808643

Hope this is still relevant, though

Cool. Thanks, @kevinam99. I never did get around to opening that PR. Sorry, @achedeuzot, for not delivering on that.

[kevinam99]

Friendly nudge @achedeuzot

[achedeuzot]

I'll be checking that later this week hopefully, I've got a 100% packed schedule 🥲

[kevinam99]

Oh :( No problem, I understand. Let me know if there's anything I could do