swh-core fixes to allow debian build

• requirements-db: Move typing-extension from test to runtime deps (to match [1])
• api.tests: Fix unsupported matches keyword to match [3]

Not necessarily for review, just making sure tox is happy

• [1] rDCOREc8a36cefa472eb6dbbfe04289a8f69ea99eab01f which fixed [2]

• [2] https://jenkins.softwareheritage.org/view/Debian%20packages/job/debian/job/packages/job/DCORE/job/gbp-buildpackage/117/console

• [3] current debian build in failure with swh/meta$716

Test Plan

tox

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Migrated from D3459 (view on Phabricator)