default VaultAuth is not generated for JWT-Auth

**Describe the bug**
When enabled is set to "true" for "defaultAuthMethod" in the Helm values.yaml
and method and mount are set to '"jwt" I expect a VaultAuth object to be created.

**To Reproduce**
Steps to reproduce the behavior:
1. Install Helm Chart application with the following values.yaml adaptations (these are the required values):
```
defaultAuthMethod:
enabled: true
method: jwt
mount: jwt
jwt:
role: jwt-role
```
2. either defaultAuthMethod/jwt/secretRef is set to an existing secret (in the operator namespace) or
defaultAuthMethod/jwt/serviceAccount is set to an existing serviceaccount (in the operator namespace)
If none is set "default" should be used as jwt/serviceAccount
4. no VaultAuth object called "default" is created (like with VaultConnection)

**Expected behavior**
If "defaultAuthMethod" is enabled in values.yaml I expect
that a default VaultAuth object is created in the "vault" namespace where
the operator is deployed.
If I just set defaultAuthMethod/jwt/serviceAccount I also expect an serviceaccountToken-secret
to be autocreated.

**Environment**
* Kubernetes version: v1.26.14
* vault-secrets-operator version: 0.6.0