MCLOUD-6651: Remove FPC patch for Magento 2.2.6

[shiftedreality]

Description

The fix was backported into 2.3.6 from 2.4.0

https://github.com/magento/magento2/commits/2.3-dev/app/code/Magento/PageCache/Model/Layout/LayoutPlugin.php

Fixed Issues (if relevant)

1. https://jira.corp.magento.com/browse/MCLOUD-6651

Manual testing scenarios

composer config repositories.mcp git git@github.com:magento/magento-cloud-patches.git
composer require "magento/magento-cloud-patches:dev-MCLOUD-6651 as 1.0.6"

1. Deploy Magento 2.3.6 with Cloud Patches 1.0.6

Release notes

For user-facing changes, add a meaningful release note. For examples, see Magento Cloud Patches release notes.

Associated documentation updates

Add link to Magento DevDocs PR or Issue, if needed.

Contribution checklist

• Pull request has a meaningful description of its purpose
• Pull request introduces user-facing changes and includes meaningful updates for any required release notes and documentation changes
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)

[miakobchuk]

QA approved.
2.3.6 Cloud instance was rebuilt successfully with this fix

[shiftedreality]

Travis CI fixes: #72