is_resource_created should return False where there is no relation

[deusebio]

Bug Description

When there are no relations, is_resource_created returns True since

all([]) == True

The correct UX that I would feel more intuitive is:

• when calling is_resource_created() with no relations, we return False
• when calling is_resource_created(relation_id) with no relation, we raise an exception

To Reproduce

N/A

Environment

N/A

Relevant log output

N/A

Additional context

No response

[carlcsaposs-canonical]

Fixed in #44