Integrations: Implement network_wide_enable to disallow inheriting env status automatically

[rebeccahum]

Description

If network_wide_enable is set to false, do not fall back on the existing env status (which would be enabled).

Pre-review checklist

Please make sure the items below have been covered before requesting a review:

• This change works and has been tested locally or in Codespaces (or has an appropriate fallback).
• This change works and has been tested on a sandbox.
• This change has relevant unit tests (if applicable).
• This change uses a rollout method to ease with deployment (if applicable - especially for large scale actions that require writes).
• This change has relevant documentation additions / updates (if applicable).
• I've created a changelog description that aligns with the provided examples.

Pre-deploy checklist

• VIP staff: Ensure any alerts added/updated conform to internal standards (see internal documentation).

Steps to Test

0. Create multisite in dev-env with added subsites 2 and 3
1. docker exec -it <container name> /bin/sh
2. in /wp/config/integrations-config/enterprise-search-config.php put this in:

<?php

return array(
	'env' => array(
		'status' => 'enabled',
		'config' => array(
			'username' => 'test-username',
			'password' => 'test-password',
			'network_wide_enable' => 'false',
		),
	),
	'network_sites' => array(
		'1' => array(
			'status' => 'enabled',
			'config' => array(
				'offload_search' => 'true',
			)
		),
		'2' => array(
			'status' => 'disabled',
			'config' => array(
				'offload_search' => 'false',
			)
		),
	)
);

3. before the PR, going to subsite 3 would automatically enable it with the inheriting. after the PR, it should no longer enable ES.

[sonarqubecloud]

Quality Gate failed

Failed conditions
C Maintainability Rating on New Code (required ≥ A)

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