Use success notice when unblocking a site (#103262)

* replace plain notice with success notice

* update test to match expected status

Author: CGastrell

client/state/data-layer/wpcom/me/block/sites/delete/index.js

@@ -6,7 +6,7 @@ import { registerHandlers } from 'calypso/state/data-layer/handler-registry';
 import { bypassDataLayer } from 'calypso/state/data-layer/utils';
 import { http } from 'calypso/state/data-layer/wpcom-http/actions';
 import { dispatchRequest } from 'calypso/state/data-layer/wpcom-http/utils';
-import { errorNotice, plainNotice } from 'calypso/state/notices/actions';
+import { errorNotice, successNotice } from 'calypso/state/notices/actions';
 import { READER_SITE_UNBLOCK } from 'calypso/state/reader/action-types';
 import { blockSite } from 'calypso/state/reader/site-blocks/actions';
 
@@ -31,7 +31,7 @@ export function fromApi( response ) {
 }
 
 export function receiveSiteUnblock() {
-	return plainNotice( translate( 'The site has been successfully unblocked.' ), {
+	return successNotice( translate( 'The site has been successfully unblocked.' ), {
 		duration: 5000,
 	} );
 }

client/state/data-layer/wpcom/me/block/sites/delete/test/index.js

@@ -27,7 +27,7 @@ describe( 'site-blocks', () => {
 			expect( dispatchedAction ).toEqual(
 				expect.objectContaining( {
 					notice: expect.objectContaining( {
-						status: 'is-plain',
+						status: 'is-success',
 					} ),
 				} )
 			);