Azure/login should logout the active account at the beginning

[MoChilia]

Azure CLI should run az logout to clear the active account at the beginning like what is done in Azure PowerShell:

login/src/PowerShell/AzPSScriptBuilder.ts

Lines 27 to 28 in 34b958d

	let commands = 'Clear-AzContext -Scope Process; ';
	commands += 'Clear-AzContext -Scope CurrentUser -Force -ErrorAction SilentlyContinue; ';

Otherwise, when the user doesn't explicitly give the subscription-id or the given subscription-id is invaild, the post steps will continue using the user's active subscription which has set last time and not logged out.

The following test case will encounter this issue:

login/.github/workflows/azure-login-negative.yml

Lines 355 to 366 in 34b958d

	# SP1 is ignored and SP2 will be used for login, but it will fail since SP2 has no access to the given subscription
	- name: Login with both creds and individual parameters
	id: login_12
	continue-on-error: true
	uses: ./
	with:
	creds: ${{secrets.SP1}}
	client-id: ${{ secrets.OIDC_SP2_CLIENT_ID }}
	tenant-id: ${{ secrets.OIDC_SP2_TENANT_ID }}
	subscription-id: ${{ secrets.OIDC_SP2_SUBSCRIPTION_ID }}
	allow-no-subscriptions: true
	enable-AzPSSession: true

[jiasli]

Perhaps az account clear for a cleaner environment?

[MoChilia]

I suppose az logout is enough for signing out the current active subscription. And the following steps will use the subscription set in azure/login. There may be a situation that customer needs to switch the active subscription by manually running az account set.

[MoChilia]

In automation, az account clear may be a better choice for a cleaner environment. I will modify the code.