Improve email change DX

[awalias]

current email change email is sent to user

• add template to supabase dashboard
• gotrue confirmation url should be a get request to users endpoint with the email_change_token as a query param, which is confirmed and returns a new valid login session (hence invalidating older refresh_tokens that may have been opened on the old email) this is current implemented here

[J0]

Hey team,

It's not that important but got here through reading up on a more recent issue. Is this issue still relevant? Seems like we have a deployed template

[J0]

Taking the liberty to close but feel free to reopen if there's more to be done w.r.t templating.

Will follow up with the sub-issues like #67 when a slot frees up. Have replicated the bug but need to discuss the fix

cc: @kangmingtay @hf