This change was caused by #26271, for configuration as below:
```
[attachment]
ENABLE = true
PATH = data/attachments
MAX_SIZE = 100
MAX_FILES = 5
```
Before #26271, the resolved path is ${AppWorkPath}/${attachments.PATH}
(such as `/var/lib/gitea/data/attachments`)
After #26271, the resolved path is ${AppDataPath}/${attachments.PATH}
(such as `/var/lib/gitea/data/data/attachments`)
Fix https://github.com/go-gitea/gitea/issues/26864
Follow https://github.com/go-gitea/gitea/pull/26271
