Merged PR 55901: Fix compilation in PHP 7.4

## What's being changed

Constructor arguments in an observer.

## Why it's being changed

The trailing comma breaks compilation in PHP 7.4.

## How to review / test this change

- Run setup:di:compile in Magento 2.3.7 on PHP 7.4.

Related work items: #262008

Observer/Newsletter/ChangeContactSubscription.php

@@ -143,7 +143,7 @@ public function __construct(
         DateTime $dateTime,
         ScopeConfigInterface $scopeConfig,
         PublisherInterface $publisher,
-        SubscriptionDataFactory $subscriptionDataFactory,
+        SubscriptionDataFactory $subscriptionDataFactory
     ) {
         $this->contactResource = $contactResource;
         $this->automationFactory = $automationFactory;