Deprecation: #89631 - Use Environment API to fetch application context 

See forge#89631

Description 

The Environment API, introduced in TYPO3 v9.3, allows access to the current Application Context (Production, Testing or Development).

The method GeneralUtility::getApplicationContext() has been deprecated, as the same information is now available in TYPO3\CMS\Core\Core\Environment::getContext().

Impact 

Calling the GeneralUtility method will trigger a PHP deprecation warning.

Affected Installations 

Any TYPO3 installation with a third-party extension calling the method directly.

Migration 

Use the Environment API call and substitute the method directly.