Remove manifest that no longer works for KDE Connect version 1.4-449 (#6124)

manifests/KDE/KDEConnect/1.4-449.yaml

@@ -1,17 +0,0 @@
-Id: KDE.KDEConnect
-Version: 1.4-449
-Name: KDE Connect
-Publisher: KDE
-License: GPL-2.0
-LicenseUrl: https://github.com/KDE/kdeconnect-kde/blob/master/LICENSES/GPL-2.0-or-later.txt
-Description: Enabling communication between all your devices. Made for people like you.
-Homepage: https://kdeconnect.kde.org/
-Tags: connect,phone,mobile,android,notification
-Installers:
-  - Arch: x64
-    Url: https://binary-factory.kde.org/job/kdeconnect-kde_Release_win64/449/artifact/kdeconnect-kde-1.4-449-windows-msvc2019_64-cl-sideload.appx
-    Sha256: 60577A29E8F8DD1D4EAAA1F8C945933E30F574D5D25AFC339B8634C2C85CA0F1
-    InstallerType: appx
-    Switches:
-          Silent: /S
-          SilentWithProgress: /S