Fix kwin for x11 not being installed.

[AWildLeon]

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• I have read the contributing guideline and understand that I have made the correct modifications

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Description:

It readd's the X11 Session and KWin (X11) since Arch Linux Removed them.
This addresses https://lists.archlinux.org/archives/list/[email protected]/thread/UV5HXCHED7U4CDUMSYEIZPYL3E3QHIE2/

Benefits of this PR and context:

How Has This Been Tested?

Yes, i tested these changes on One of my servers. like described in CONTRIBUTING.md
(Except for ARM, i don't have a VM with Nesting)

Source / References:

https://lists.archlinux.org/archives/list/[email protected]/thread/UV5HXCHED7U4CDUMSYEIZPYL3E3QHIE2/

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[LinuxServer-CI]

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https://ci-tests.linuxserver.io/lspipepr/webtop/arch-kde-2025-06-20-pkg-ea680b1b-dev-9fafd04d499d2d6b086604830645fc4d44f78448-pr-333/index.html
https://ci-tests.linuxserver.io/lspipepr/webtop/arch-kde-2025-06-20-pkg-ea680b1b-dev-9fafd04d499d2d6b086604830645fc4d44f78448-pr-333/shellcheck-result.xml

Tag	Passed
amd64-arch-kde-2025-06-20-pkg-ea680b1b-dev-9fafd04d499d2d6b086604830645fc4d44f78448-pr-333	✅
arm64v8-arch-kde-2025-06-20-pkg-ea680b1b-dev-9fafd04d499d2d6b086604830645fc4d44f78448-pr-333	✅

[LinuxServer-CI]

I am a bot, here are the test results for this PR:
https://ci-tests.linuxserver.io/lspipepr/webtop/arch-kde-2025-06-20-pkg-ea680b1b-dev-db0835ca52fc51781ebd69dfa784d1bfdc64cc01-pr-333/index.html
https://ci-tests.linuxserver.io/lspipepr/webtop/arch-kde-2025-06-20-pkg-ea680b1b-dev-db0835ca52fc51781ebd69dfa784d1bfdc64cc01-pr-333/shellcheck-result.xml

Tag	Passed
amd64-arch-kde-2025-06-20-pkg-ea680b1b-dev-db0835ca52fc51781ebd69dfa784d1bfdc64cc01-pr-333	✅
arm64v8-arch-kde-2025-06-20-pkg-ea680b1b-dev-db0835ca52fc51781ebd69dfa784d1bfdc64cc01-pr-333	✅

[thelamer]

Thanks for the fix