feat(scm): Add get_archive_link to SCM API

[billyvg]

This adds a new API to get a download repository URL. Note that GitHub returns 302 with a presigned URL in the Location header whereas GitLab streams the content directly. I believe we also need to supply an auth header for GitLab as well (but havent confirmed yet).

This is needed to replicate behavior for downloading a repo in Seer

[linear-code]

CW-1049 Add `get_archive_link` action to SCM

[github-actions]

Backend Test Failures

Failures on 46e88ad in this run:

tests/sentry/scm/unit/test_gitlab_provider.py::TestGetArchiveLink::test_empty_ref_omits_sha_param — log

tests/sentry/scm/unit/test_gitlab_provider.py:13104: in test_empty_ref_omits_sha_param
    client.get_access_token.return_value = {
/opt/hostedtoolcache/Python/3.13.1/x64/lib/python3.13/unittest/mock.py:688: in __getattr__
    raise AttributeError("Mock object has no attribute %r" % name)
E   AttributeError: Mock object has no attribute 'get_access_token'

tests/sentry/scm/unit/test_gitlab_provider.py::TestGetArchiveLink::test_returns_tar_gz_url — log

tests/sentry/scm/unit/test_gitlab_provider.py:13074: in test_returns_tar_gz_url
    client.get_access_token.return_value = {
/opt/hostedtoolcache/Python/3.13.1/x64/lib/python3.13/unittest/mock.py:688: in __getattr__
    raise AttributeError("Mock object has no attribute %r" % name)
E   AttributeError: Mock object has no attribute 'get_access_token'

tests/sentry/scm/unit/test_gitlab_provider.py::TestGetArchiveLink::test_returns_zip_url — log

tests/sentry/scm/unit/test_gitlab_provider.py:13089: in test_returns_zip_url
    client.get_access_token.return_value = {
/opt/hostedtoolcache/Python/3.13.1/x64/lib/python3.13/unittest/mock.py:688: in __getattr__
    raise AttributeError("Mock object has no attribute %r" % name)
E   AttributeError: Mock object has no attribute 'get_access_token'

[github-actions]

Backend Test Failures

Failures on f49cd51 in this run:

tests/sentry/scm/unit/test_github_provider.py::TestGetArchiveLink::test_returns_archive_url — log

tests/sentry/scm/unit/test_github_provider.py:1355: in test_returns_archive_url
    result = provider.get_archive_link("main")
src/sentry/scm/private/providers/github.py:135: in wrapper
    return fn(*args, **kwargs)
src/sentry/scm/private/providers/github.py:718: in get_archive_link
    github_format = GITHUB_ARCHIVE_FORMAT_MAP[archive_format]
E   KeyError: 'tar.gz'

tests/sentry/scm/unit/test_github_provider.py::test_raises_scm_provider_exception_on_api_error[get_archive_link-kwargs47] — log

tests/sentry/scm/unit/test_github_provider.py:140: in test_raises_scm_provider_exception_on_api_error
    getattr(provider, method)(**kwargs)
src/sentry/scm/private/providers/github.py:135: in wrapper
    return fn(*args, **kwargs)
src/sentry/scm/private/providers/github.py:718: in get_archive_link
    github_format = GITHUB_ARCHIVE_FORMAT_MAP[archive_format]
E   KeyError: 'tar.gz'