allowRTL (and forceRTL) set in index.tsx file won't get set early enough to be used

Environment

Run the following in your terminal and copy the results here.

1. npx react-native --version: 4.13.0
2. npx react-native info:
   System:
   OS: Windows 10 10.0.19042
   CPU: (20) x64 Intel(R) Xeon(R) W-2255 CPU @ 3.70GHz
   Memory: 41.07 GB / 63.69 GB
   Binaries:
   Node: 10.15.0 - C:\Program Files\nodejs\node.EXE
   Yarn: Not Found
   npm: 6.4.1 - C:\Program Files\nodejs\npm.CMD
   Watchman: Not Found
   SDKs:
   Android SDK: Not Found
   Windows SDK:
   AllowDevelopmentWithoutDevLicense: Enabled
   AllowAllTrustedApps: Enabled
   Versions: 10.0.17763.0, 10.0.18362.0
   IDEs:
   Android Studio: Not Found
   Visual Studio: 15.9.28307.1300 (Visual Studio Enterprise 2017), 16.8.30711.63 (Visual Studio Enterprise 2019)
   Languages:
   Java: Not Found
   Python: 2.7.15 - C:\Users\emrou.windows-build-tools\python27\python.EXE
   npmPackages:
   @react-native-community/cli: 4.13.0 => 4.13.0
   react: 16.13.1 => 16.13.1
   react-native: 0.63.3 => 0.63.3
   react-native-windows: 0.63.6 => 0.63.6
   npmGlobalPackages:
   react-native: Not Found

What device(s) are you targeting? Choose any from Desktop, Xbox, Hololens)

• Target Device(s): Desktop
  Which version of Visual Studio are you using? Specify Visual Studio 2017 or Visual Studio 2019
• Visual Studio Version: 2019

Steps To Reproduce

Provide a detailed list of steps that reproduce the issue.

1. Turn on RTL language for RNW XB GP app
2. App does the RTL formatting

However, with NativeUIManager.addRootView, when querying isRTL, it will return false due to allowRTL being set to false. Trying to do I18nManager.allowRTL(true) in our earliest tsx file will set the property to true, but past the initial root view rendering, which will then mean the app will be still in LTR configuration.

Expected Results

If I set allowRTL in the index.tsx/bootstrapping file of our RNW code the native I18nManager would see and re-render as needed OR have a way for us to set allowRTL to be true in some native code or config file.

If I just hardcode I18nManager.isRTL to return true, the app will appropriately be configured in the RTL format.

Snack, code example, screenshot, or link to a repository:

N/A or engage offline

Start with the index.tsx bootstrapping path and trace how I18nManager.allowRTL and isRTL interact with NativeUIManager.addRootView during initial rendering. Reproduce with the RTL language setting and verify that a setting made in index.tsx affects the initial native root view, or that the requested native configuration path is available.