Existing secret values get recreated via RandomSecret even when no rotation is configured and policy is Retain (after #300)

[tbalzer]

We observe that after updating from 0.8.38 to 0.8.46 secret values get recomputed in vault now, although this is undesired as they have no rotation configured and the secret value already existed.

We suspect #300 (comment) is the cause for this.

[raffaelespazzoli]

this should be fixed in released 0.8.48