tests: fix PHP deprecated notice - Automatic conversion of false to array

[Ta5r]

Tracking wpengine#283

What

This PR fixes deprecation warnings in several PHPUnit tests caused by accessing an undefined get_option('graphql_general_settings').

Important

This PR is based on wpengine#280 and requires it to be merged first

Why

The deprecated warnings were being shown on running the composer tests.

How

• Ensure $settings is an array before updating one of it's values.

Screenshot :

Before :

No more deprecation warnings ✅

[justlevine]

For the screenshot: add a before from running the test on wpengine/main's branch.

[Ta5r]

For the screenshot: add a before from running the test on wpengine/main's branch.

Done 👍 ✅

[justlevine]

@Ta5r

I rebased on wpengine#280 to remove unnecessary dependencies.

Last step before you can open your PR on wpengine: generate a changeset:

1. run npm run changeset

2. The fixes in here are a patch, they're not adding new features/enhancements.

3. Use conventional commits for the changlog message. In this case we want something along the lines of tests: fix PHP deprecation notices.

[justlevine]

A more succint way for handling all of these:

Suggested change

	$settings = get_option( 'graphql_general_settings' );
	if ( ! is_array( $settings ) ) {
	$settings = [];
	}
	$settings = get_option( 'graphql_general_settings', [] );

[justlevine]

LGTM 🚀

@Ta5r go ahead and open a PR for this branch against wpengine:main, copy over the PR title + description, and then tag me in a comment.