feat(gotrue): Add phone mfa enrollment

[dshukertjr]

What kind of change does this PR introduce?

feature of adding phone support for MFA enrollment

JS PR here: supabase/auth-js#932

What is the current behavior?

Enrolling in MFA via SMS is supported .

What is the new behavior?

SMS MFA is not supported.

[coveralls]

Pull Request Test Coverage Report for Build 15534668729

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 25 of 32 (78.13%) changed or added relevant lines in 2 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.2%) to 75.624%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/gotrue/lib/src/types/mfa.dart	10	17	58.82%

Files with Coverage Reduction	New Missed Lines	%
packages/functions_client/lib/src/functions_client.dart	1	96.49%
packages/gotrue/lib/src/fetch.dart	1	91.36%

Totals
Change from base Build 15425969446:	0.2%
Covered Lines:	2907
Relevant Lines:	3844

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💛 - Coveralls

[dshukertjr]

I know this isn't great, but I think we can call it that it's a fix. Open to suggestions to avoid this though.

[grdsdev]

See my comment in https://github.com/supabase/supabase-flutter/pull/1188/files#r2131807418