Replace all contexts in tests with go1.24 t.Context()
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Co-authored-by: Giteabot <teabot@gitea.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
By using git's ability, end users (especially small instance users) do
not need to enable the indexer, they could also benefit from the code
searching feature.
Fix#29996


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Co-authored-by: silverwind <me@silverwind.io>