[expo-splash-screen] `SplashScreen.preventAutoHideAsync()` no longer works in iOS

🐛 Bug Report

Summary of Issue

Calling SplashScreen.preventAutoHideAsync() does not prevent hiding the splash screen in expo-splash-screen@0.4.0. The splash screen automatically hides by itself.

Note that this break was introduced in 0.4.0 – it works in 0.3.1!

The issue appears on iOS only (could not reproduce in Android).

Environment – output of expo diagnostics & the platform(s) you’re targeting

  Expo CLI 3.21.13 environment info:
    System:
      OS: macOS 10.15.5
      Shell: 5.7.1 - /bin/zsh
    Binaries:
      Node: 12.18.1 - ~/.nvm/versions/node/v12.18.1/bin/node
      Yarn: 1.22.4 - ~/Development/charisma/charisma-mobile/node_modules/.bin/yarn
      npm: 6.14.5 - ~/.nvm/versions/node/v12.18.1/bin/npm
    IDEs:
      Android Studio: 4.0 AI-193.6911.18.40.6514223
      Xcode: 11.5/11E608c - /usr/bin/xcodebuild
    npmPackages:
      react: 16.11.0 => 16.11.0
      react-native: 0.62.2 => 0.62.2

Reproducible Demo

import React from "react";
import { Text } from "react-native";
import * as SplashScreen from "expo-splash-screen";

SplashScreen.preventAutoHideAsync().catch(console.warn);

export default () => <Text>Hello world</Text>;

No warning is emitted, but the splash screen automatically hides.

Will aim to get a full repo up over the weekend!

I also feel this is related to PR #8739.