Added iOS social login

[mzparacha]

Link to Issue

Closes: #6509

Description of Changes

• Adds iOS/apple login in the new AuthModal -> "Email or social" tabs

"How We Fixed It"

N/A

Test Plan

• Enable FLAG_NEW_SIGN_IN_MODAL in .env
• Logout, visit any page in the app and open AuthModal -> "Email or social" tabs
• Click on the "Apple" button and verify that it logs you in correctly.

Deployment Plan

N/A

Other Considerations

N/A

[mhagel]

I found a bug unrelated to your change. Just a 1-liner, so I committed it here. 73be644

[mhagel]

Tested with iphone. Worked great.

[dillchen]

Works for me

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Out of scope

1. Discuss which login options to show users on mobile (show a subset of wallet and social)
2. Figure out later on how we get a better flow on finishSocialLogin it's so slow, half magic's fault, but otherwise things we could fix
3. Getting this when testing locally - finish social login just took a long time after this and worked: