Add token expiration handling for AzureMFA auth (#16936)

* refresh azure account token if it's expired before sending query/list requests

* fix several connection checks && add more logging

* fix async UI glitch during token refreshing

* cleanup

* minor fix

* add test for refreshAzureAccountTokenIfNecessary

* address comments

* comments

* comments

* comments

* error handling

src/sql/azdata.proposed.d.ts

@@ -947,4 +947,13 @@ declare module 'azdata' {
 		 */
 		parentTypeName?: string;
 	}
+
+	export namespace accounts {
+		export interface AccountSecurityToken {
+			/**
+			 * Access token expiry timestamp
+			 */
+			expiresOn?: number
+		}
+	}
 }