remove extra labels from vault in fluentbit

fix the following:

2 errors like: entry for stream '{app_kubernetes_io_instance="vault-vault", app_kubernetes_io_name="vault", app_kubernetes_io_version="1.19.3", cluster="logging-loki", component="server", container="vault", controller_revision_hash="vault-vault-7dcdcf5f57", job="fluentbit", namespace="vault", node_name="w3", pod="vault-vault-0", vault_active="false", vault_initialized="false", vault_perf_standby="false", vault_sealed="true", vault_version="1.19.3"}' has 16 label names; limit 15