Add keyword AADSTS50020 to metadata.

adding at least one keyword

Author: NuAlex

support/entra/entra-id/app-integration/error-code-AADSTS50020-user-account-identity-provider-does-not-exist.md

@@ -6,7 +6,7 @@ ms.editor: v-jsitser
 ms.reviewer: rrajan, haelshab, sungow, v-leedennis
 ms.service: entra-id
 ms.custom: sap:Issues Signing In to Applications, has-azure-ad-ps-ref
-keywords:
+keywords: AADSTS50020
 #Customer intent: As a Microsoft Entra administrator, I want to figure out why error code AADSTS50020 occurs so that I can make sure that my guest users from an identity provider can sign in to a resource tenant.
 ---
 # Error AADSTS50020 - User account from identity provider does not exist in tenant