Apple TV support 1: podspec and code changes for commonly used modules (#24329)

# Why

First of a series of PRs to add Apple TV support for many (but not all)
Expo SDK modules.

This PR makes A

Apple TV support 1: podspec and code changes for commonly used modules (#24329)

# Why

First of a series of PRs to add Apple TV support for many (but not all)
Expo SDK modules.

This PR makes Apple TV able to compile for apps using
`[email protected]` and ONLY the following modules:

- expo
- expo-application
- expo-constants
- expo-eas-client
- expo-file-system
- expo-font
- expo-json-utils
- expo-keep-awake
- expo-manifests
- expo-modules-core
- expo-splash-screen
- expo-structured-headers
- expo-updates-interface
- expo-updates

# How

- Add tvOS to podspecs
- Native code changes wrapped in `#if TARGET_OS_TV` (for Objective C) or
`#if os(tvOS)` (for Swift)
- Import source for the `ASN1Decoder` Swift framework used by
`expo-updates`, as the public podspec for that framework does not yet
support tvOS

# Test Plan

- Manual testing with a template still in development
- Existing CI for iOS should pass (nothing should be broken)

# Checklist

<!--
Please check the appropriate items below if they apply to your diff.
This is required for changes to Expo modules.
-->

- [x] Documentation is up to date to reflect these changes (eg:
https://docs.expo.dev and README.md).
- [x] Conforms with the [Documentation Writing Style
Guide](https://github.com/expo/expo/blob/main/guides/Expo%20Documentation%20Writing%20Style%20Guide.md)
- [x] This diff will work correctly for `npx expo prebuild` & EAS Build
(eg: updated a module plugin).

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