[TASK] Remove PHP 8.0 and PHP 8.1 polyfills from ext:core

With #96749 superflous polyfills has been removed from root
composer.json. This patch removes missed occurrences in the
composer.json of ext:core.

used command:

> composer rem symfony/polyfill-php80 -d typo3/sysext/core \
  --no-update
> composer rem symfony/polyfill-php81 -d typo3/sysext/core \
  --no-update

Resolves: #96756
Related: #96749
Releases: main
Change-Id: I8205b898b4a11af5d00f7aea425a5abba3803ba3
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73314


Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>