fix(storage): add upsert option for signed bucket

[silentworks]

What kind of change does this PR introduce?

Currently there is no way to upsert with a signed upload url, this is because the create_signed_upload_url method doesn't have an option for upsert. This PR aims to fix this as the upsert should be indicated at the URL creation stage and not at the upload stage.

Additional context

Documentation change will need to happen for the Python reference docs too.

Fixes #1254

[o-santi]

Unnecessary import.

[o-santi]

Unnecessary import.

[coveralls]

Pull Request Test Coverage Report for Build 18948167546

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.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 332 unchanged lines in 18 files lost coverage.
• Overall coverage decreased (-1.2%) to 92.687%

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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:	8517
Relevant Lines:	9189

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💛 - Coveralls