[Docs]: PHP Upgrade guide tells you to disable platform checks

### Issue Type

Missing documentation

### Documentation Location

https://docs.altis-dxp.com/guides/updating-php/

### Issue Description

Currently our PHP upgrade guide tells you to disable platform-checks, this means if you upgrade to a newer version of Altis while upgrading PHP, you're not going to get any PHP version failures if you roll out the codebase to an older version of PHP in altis cloud.

For example:

1. Have PHP 8.1 codebase on Altis 20
1. Upgrade to Altis 25, and planning to do PHP 8.3. Add the ignore platform-checks
1. Deploy codebase to PHP 8.1

You never get an errors that your codebase is not 8.1 compatible, because we're telling people to disable platform checks.

### Current Content

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### Suggested Improvement

```markdown

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### Additional Info

_No response_