Following your advice here, I was also able to collect the logs from azure storage accounts using persistent volumes mounted to another promtail instance /var/log directory.
I used this config:
scrape_configs:
- job_name: system
static_configs:
- targets:
- localhost
labels:
job: varlog
__path__: /var/log/**/*.log
Also elaboraetd more on this [here] (Ingesting logs from Azure Blob Storage to Loki - Stack Overflow)