[enhancement]: AzureCLI task's Azure login with az cli should be optional

### Task name

AzureCLI

### Describe your feature request here

AzureCLI@2 and AzureCLI@3 emits federation idToken to idToken environment variable when `addSpnToEnvironment` is true.

On our use case we use AzureCLI@3 with addSpnToEnvironment to get idToken and fetch our token(s) from Entra ID without using az cli at all.

To make task faster it should be possible to fully skip `az login` when using `addSpnToEnvironment`

Locate the AzureCLI@2 and AzureCLI@3 task implementations and trace where az login runs relative to addSpnToEnvironment and the idToken environment variable. Add an option to skip az login while still exposing the requested federation token, then verify that the existing login behavior remains unchanged when the option is not used.

Written by the indexing model from the issue text.