Change required arguments for az account set command as optional

**Related command**
az account set

**Is your feature request related to a problem? Please describe.**
No, quality of life improvement for interactive sessions.

**Describe the solution you'd like**
The new interactive login experience introduced in version 2.61.0 is awesome. The table to select the subscription is convenient. Why not display the table again when running `az account set` with no arguments at all instead of erroring out saying "the following arguments are required: --subscription/-s/--name/-n`"?

**Describe alternatives you've considered**
None. Currently we'd need to run `az account list --output table` THEN copy either the Name or SubscriptionId THEN pass it into the az account set command with the proper argument. It's a bit annoying for users with 6+ subscriptions that they work with every day.

**Additional context**
Current experience:

Requested experience:
`PS C:\> az account set

[Tenant and subscription selection]

No Subscription name Subscription ID Tenant
----- ------------------------------------ ------------------------------------ ------------

The default is marked with an *; the default tenant is '' and subscription is '' ().

Select a subscription and tenant (Type a number or Enter for no changes):
`