fix regex of matching hetzner dns api error responses

[lindsayzhou]

'"error":{[^}]*}' is a invalid regexp for busybox egrep:

$ docker run -it --rm busybox:1.36 ash
/ # echo '"error":{"details": "message"}' | /bin/busybox egrep '"error":{[^}]*}'
egrep: bad regex '"error":{[^}]*}': Invalid content of \{\}
/ # echo '"error":{"details": "message"}' | /bin/busybox egrep '"error":\{[^\}]*\}'
"error":{"details": "message"}

There is a similar and correct regexp at

acme.sh/acme.sh

Line 5074 in f981c78

error="$(echo "$response" | _egrep_o '"error":\{[^\}]*')"

[github-actions]

Welcome
First thing: don't send PR to the master branch, please send to the dev branch instead.
Please make sure you've read our DNS API Dev Guide and DNS-API-Test.
Then reply on this message, otherwise, your code will not be reviewed or merged.
Please also make sure to add/update the usage here: https://github.com/acmesh-official/acme.sh/wiki/dnsapi2
We look forward to reviewing your Pull request shortly ✨
注意: 必须通过了 DNS-API-Test 才会被 review. 无论是修改, 还是新加的 dns api, 都必须确保通过这个测试.

[lindsayzhou]

This is a pretty small PR.
Should this also run DNS-API-TEST ?

[lindsayzhou]

OK, there are other issues on OpenBSD: https://github.com/lindsayzhou/acme.sh/actions/runs/12739946412/job/35506131990#step:4:1880

I'll fix it in my spare time.