Avoid empty asset updates

[kamilon]

This PR makes 4 changes to the flow:

1. When the data received from Tibia.com is not in the expected shape, exit with code 1 to fail the workflow.
2. Retry getting data up to 5 (from 2) times with exponential backoff (1s, 2s, 4s, 8s, 16s).
3. If house data is not successful after all attempts, exit with code 1 to fail the workflow.
4. If worlds or houses is empty when getting data from Tibia.com, the site must be in maintenance mode, exit with code 1 to fail the workflow.

Errors are logged in all 4 cases.

Fix a typo in logging.