fluxcd_bootstrap_git does not re-create flux-system secret

[ketbla]

We've been using fluxcd and it works great, however now we're trying to rotate secrets and that seems to be broken with terraform.

According to the guide https://fluxcd.io/flux/installation/configuration/deploy-key-rotation/ we are supposed to:

1. Delete secret in flux-system
2. Re-run fluxcd bootstrap to re-create it

However when using terraform resource fluxcd_bootstrap_git, it does not detect that the secret was deleted and does not re-create it.

Steps to reproduce:

1. run `kubectl delete secret flux-system -n flux-system
2. Re-run terraform
3. No changes, infrastructure up to date

Because of this, it makes it impossible to rotate keys for people using terraform to bootstrap fluxcd.