Azure Key Vault Secret - Service Principal list derives from global. Folder level isn't showing as a choice

[tesatt]

We run Jenkins as a community. Folder users can't see other folder users. Credentials in folder level are important to us.

When adding Azure Key Vault Secret - the Service Principal choice derives only from the global level. When we add a Service Principal to the folder level, Azure Key Vault Secret doesn't see it. It only sees what is added to the global level.

We'd like this plugin to be able to see Service Principals that are added at the folder level. This will ensure separation of credentials between teams.

To reproduce:
Create a Service Principal at the global credentials level
Create a Service Principal at the folder level
Create an Azure Key Vault Secret at the folder level
-Choose Service Principal drop down menu. You'll see that only your global SP can be seen. This creates a major problem for our users.

[timja]

Contributions welcome, I don't have much time here but can review / test PRs. Otherwise I'll get to it at some point