Vault JWT authentication not working
## Describe the bug
The JWT authentication on Vault does not work.
## Expected behavior
When setting `VAULT_JWT_TOKEN` and not setting `VAULT_ROLE_ID` and `VAULT_SECRET_ID`, `vault_secrets_provider` should use the JWT authentication method when connecting to Vault.
## Actual behavior
Instead, `vault_secrets_provider` uses the approle authentication method when connecting to Vault.
## Logs and/or screenshots
```
Failed retrieving KV engine version > Login failed > Vault server error on POST https://vault.secrets.tech.orange/v1/auth/approle/login > invalid role ID'
```
## Context & Configuration
Link to a project, pipeline or job facing the bug: (please provide one if possible)
The issue was reproduced using:
* Version of the template: 1.2.5
* GitLab server(s): self-managed CE
* GitLab runner(s):
issue