Avoid severe logging on AzureVault if secret is not found

[ndr-brt]

Feature Request

Currently AzureVault logs an exception if the secret is not fount through the resolveSecret method.
It shouldn't, since it's something that needs to be evaluated from the client class (in some cases, e.g. DataPlaneS3Extension, if the credentials are not found in the vault they are loaded in a different way, so it's not an error).

Which Areas Would Be Affected?

azure vault

Why Is the Feature Desired?

Avoid misleading error logs

Solution Proposal

If possible, provide a (brief!) solution proposal.

Type of Issue

i.e., new feature, improvement, cleanup, etc.

Checklist

• assigned appropriate label?
• Do NOT select a milestone or an assignee!