Cache access tokens in local cache file to prevent MSAL throttling (#22763)

src/sql/platform/accounts/test/common/testAccountManagementService.ts

@@ -107,6 +107,7 @@ export class AccountProviderStub implements azdata.AccountProvider {
 	getAccountSecurityToken(account: azdata.Account, tenant: string, resource: azdata.AzureResource): Thenable<{ token: string }> {
 		return Promise.resolve(undefined!);
 	}
+
 	initialize(storedAccounts: azdata.Account[]): Thenable<azdata.Account[]> {
 		return Promise.resolve(storedAccounts);
 	}