Add @Expensify to React Native incubating partners list (#37497)

Summary:
Adding Expensify to the React Native incubating partners list

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[Internal] - Adding Expensify to the React Native incubating partners list

Pull Request resolved: https://github.com/facebook/react-native/pull/37497

Test Plan: N/A - Just documentation update

Reviewed By: TheSavior

Differential Revision: D47002327

Pulled By: rickhanlonii

fbshipit-source-id: 39adf1e519e32aaf911baacb78a5549109d4c0c0

ECOSYSTEM.md

@@ -38,7 +38,7 @@ Examples of contributing to the release include being a [community releaser](htt
 * **[Wix.com](https://wix.engineering/open-source):** Maintains a variety of React Native open source projects ([see all](https://github.com/orgs/wix/repositories?q=react-native)), including:  [Detox](https://wix.github.io/Detox/) end-to-end testing library for React Native apps, [RN UILib](https://wix.github.io/react-native-ui-lib/), [RN Navigation](https://wix.github.io/react-native-navigation/), [RN Calendars](https://wix.github.io/react-native-calendars/) and [RN Notifications](https://github.com/wix/react-native-notifications).
 
 ### Incubating partners:
-* There are no current incubating partners.
+* **[Expensify](https://expensify.com/):** Developing [Expensify Chat](https://github.com/Expensify/App), an open-source React Native app built by the community, while [sponsoring dependencies](https://github.com/orgs/Expensify/sponsoring), conferences, and New Architecture advancements.
 
 When you are contributing to React Native, you'll most likely meet somebody who works at one of the partner companies and who is a core contributor.