[CLEANUP] Remove invalid paths in PSR-4 section

Remove not existing paths from root composer.json.
For 8.7 the path to context_help must be kept.

Resolves: #82546
Releases: master, 8.7
Change-Id: Iea32a481011d906ea7057072413e6ae01a2ce771
Reviewed-on: https://review.typo3.org/54211


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Reviewed-by: Jan Stockfisch <jan.stockfisch@googlemail.com>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>

composer.json

@@ -137,7 +137,6 @@
 			"TYPO3\\CMS\\Backend\\": "typo3/sysext/backend/Classes/",
 			"TYPO3\\CMS\\Belog\\": "typo3/sysext/belog/Classes/",
 			"TYPO3\\CMS\\Beuser\\": "typo3/sysext/beuser/Classes/",
-			"TYPO3\\CMS\\ContextHelp\\": "typo3/sysext/context_help/Classes/",
 			"TYPO3\\CMS\\Core\\": "typo3/sysext/core/Classes/",
 			"TYPO3\\CMS\\Cshmanual\\": "typo3/sysext/cshmanual/Classes/",
 			"TYPO3\\CMS\\Documentation\\": "typo3/sysext/documentation/Classes/",
@@ -152,7 +151,6 @@
 			"TYPO3\\CMS\\Frontend\\": "typo3/sysext/frontend/Classes/",
 			"TYPO3\\CMS\\Impexp\\": "typo3/sysext/impexp/Classes/",
 			"TYPO3\\CMS\\IndexedSearch\\": "typo3/sysext/indexed_search/Classes/",
-			"TYPO3\\CMS\\IndexedSearchMysql\\": "typo3/sysext/indexed_search_mysql/Classes/",
 			"TYPO3\\CMS\\Info\\": "typo3/sysext/info/Classes/",
 			"TYPO3\\CMS\\InfoPagetsconfig\\": "typo3/sysext/info_pagetsconfig/Classes/",
 			"TYPO3\\CMS\\Install\\": "typo3/sysext/install/Classes/",