Cannot open token authentication

**Describe the bug**
Cannot open token authentication.

**To Reproduce**
Steps to reproduce the behavior:
1. download pulsar 2.9.1 in release
2. edit `conf/standalone.conf`
```conf
# Enable authentication
authenticationEnabled=true

# Authentication provider name list, which is comma separated list of class names
authenticationProviders=org.apache.pulsar.broker.authentication.AuthenticationProviderToken

# Enforce authorization
authorizationEnabled=true

# Authorization provider fully qualified class-name
authorizationProvider=org.apache.pulsar.broker.authorization.PulsarAuthorizationProvider

tokenSecretKey=/path/to/my-secret.key
```
No other configuration changes
3. run `bin/pulsar standalone`
4. See error

**Expected behavior**
pulsar runs normally and opens token authentication

**Screenshots**

**Desktop (please complete the following information):**
- OS: Ubuntu

Reproduce the startup failure using conf/standalone.conf with token authentication enabled, then run bin/pulsar standalone and capture the full error rather than relying on the linked screenshot. Trace the tokenSecretKey and authentication provider configuration to identify why Pulsar 2.9.1 fails to start; done means standalone starts normally with token authentication enabled.

Written by the indexing model from the issue text.