Fix commit retrieval by tag (#21804)
It is not correct to return tag data when commit data is requested, so
remove the hacky code that overwrote parts of a commit with parts of a
tag.
This fixes commit retrieval by tag for both the latest commit in the UI
and the commit info on tag webhook events.
Fixes: https://github.com/go-gitea/gitea/issues/21687
Replaces: https://github.com/go-gitea/gitea/pull/21693
<img width="324" alt="Screenshot 2022-11-13 at 15 26 37"
src="https://user-images.githubusercontent.com/115237/201526975-736c6ea7-ad6a-467a-a823-9a63d6ecb718.png">
<img width="789" alt="image"
src="https://user-images.githubusercontent.com/115237/201526876-90a13ffc-1e5c-4d76-911b-f1ae51e8eaab.png">
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Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
ea1d09718c
