Azure KeyVault provider returns error when disabled secret is contained within KV #436

Describe the bug
We have discovered that the provider returns an error when trying to load secrets if one of the secrets has been disabled (Azure returns 403 Forbidden)

To Reproduce
Have an Azure KeyVault
Add secret
Disable said secret
Fetch secrets using the provider

Expected behavior
I see 2 possibilities to address the issue:

1. Add an option to permit to skip secrets that do 403 when getting them
2. Instead of returning error, the interface allows to return an interface, couldn't you set the error as the key's value and then check for error later in the parsing? You might not even need that secret anyway

Please provide the following information):

• OS: windows
• Koanf v2.3.5
• Koanf azure provider v0.1.0

Additional context
We will suggest a fix in a PR soon, but discussion can occur here