fix(auth): mypy auth

[o-santi]

What kind of change does this PR introduce?

Fix typing definitions for auth, enough for mypy to accept them.

Additional context

Most of the changes were to remove _request's callback parameter, xform, because it is much more difficult to type it correctly than to just run the function manually. It also simplifies the code for a later refactor on sync/async.

Most of the helper tests also had to be changed, because they override model_validate and make the function accept any invalid data passed in. Some things still need to change, like the manual URL concatenation, or the multiple Anys, but that's coming in a future rewrite.

[coveralls]

Pull Request Test Coverage Report for Build 18916340641

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 318 unchanged lines in 16 files lost coverage.
• Overall coverage decreased (-1.2%) to 92.703%

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Files with Coverage Reduction	New Missed Lines	%
tests/test_helpers.py	2	98.92%
src/supabase_auth/types.py	3	98.65%
tests/_sync/test_gotrue.py	3	99.03%
tests/_sync/test_gotrue_admin_api.py	3	98.83%
src/supabase_auth/_async/gotrue_base_api.py	3	91.89%
tests/_async/test_gotrue.py	3	99.03%
src/supabase_auth/_sync/gotrue_base_api.py	3	91.89%
src/supabase_auth/_sync/gotrue_admin_api.py	5	90.91%
tests/_async/test_gotrue_admin_api.py	5	98.05%
src/supabase_auth/_async/gotrue_admin_api.py	5	90.91%

Totals
Change from base Build 18888484625:	-1.2%
Covered Lines:	8512
Relevant Lines:	9182

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💛 - Coveralls