[bugfix] incorrect /api/v_/instance domain uri fields

[NyaaaWhatsUpDoc]

Description

closes #3467

Checklist

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[tsmethurst]

Looks good. We should probably think about removing account_domain at some point then since it turns out it's superfluous.

[NyaaaWhatsUpDoc]

Looks good. We should probably think about removing account_domain at some point then since it turns out it's superfluous.

yeah i was unsure of that... at the moment it can be used to tell if a separate account_domain exists, but then i suppose they can already tell that as they know the host to be dialling the instance endpoint :p

[tsmethurst]

Yeah indeed 🤔 Could you make an issue for removing it? We just need to investigate what uses it (can't remember why we added it) and change it to use uri instead, basically.