git tag -h fatal error with global tag.sort config

[Bagas Sanjaya <bagasdotme@xxxxxxxxx>]

Hi,

I stumbled on Debian bug report [1], and I can reproduce the bug.

In global config (~/.gitconfig), I set:

```
[tag]
	sort = creatordate
```

When I run `git tag -h` inside a Git repository (such as git.git), 
instead of usage summary, I got:

```
fatal: not a git repository, but the field 'creatordate' requires access 
to object data
```

But plain `git tag` works fine.

This bug occurs on v2.33.0 as well as version in the original bug report 
(v2.26.0-rc2) and v2.25.1.

[1]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=954811

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