Fix babel-plugin-codegen crash when export init is null

[janicduplessis]

Summary

It is possible that init is null when using the following code.

export var a;

The typescript compiler actually generates something like this for enums so a lot of third party libraries triggered this issue.

For example in expo-apple-authentication/build/AppleAuthentication.types.js

export var AppleAuthenticationScope;
(function (AppleAuthenticationScope) {
    AppleAuthenticationScope[AppleAuthenticationScope["FULL_NAME"] = 0] = "FULL_NAME";
    AppleAuthenticationScope[AppleAuthenticationScope["EMAIL"] = 1] = "EMAIL";
})(AppleAuthenticationScope || (AppleAuthenticationScope = {}));

This simply adds a null check.

Changelog

[General] [Fixed] - Fix babel-plugin-codegen crash when export init is null

Test Plan

Tested that this fixed the crash in an app.

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
ios	-	universal	n/a	--

Base commit: 2829146
Branch: main

[facebook-github-bot]

@philIip has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[philIip]

hi @janicduplessis, can you rebase your changes? i will go for the land when possible. thanks for working on this!

[janicduplessis]

@philIip done!

[analysis-bot]

Platform	Engine	Arch	Size (bytes)	Diff
android	hermes	arm64-v8a	8,214,206	+0
android	hermes	armeabi-v7a	7,799,915	+0
android	hermes	x86	8,587,706	+0
android	hermes	x86_64	8,538,641	+0
android	jsc	arm64-v8a	9,882,916	+0
android	jsc	armeabi-v7a	8,853,159	+0
android	jsc	x86	9,852,501	+0
android	jsc	x86_64	10,447,566	+0

Base commit: 2829146
Branch: main

[facebook-github-bot]

@philIip has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[react-native-bot]

This pull request was successfully merged by @janicduplessis in ae75664.

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