redshift-plasma-applet: patch to work with redshift 1.12 update

From patch commit message:

> Redshift version >= 1.12 requires the -P option to clear the
> existing gamma ramps for one-shot mode. Without it the screen
> gets darker and darker until it is impossible to see anything.

Apply this fix since a new version of the applet has not been
released.

pkgs/applications/misc/redshift-plasma-applet/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, cmake, extra-cmake-modules, plasma-framework, kwindowsystem, redshift, fetchFromGitHub, }:
+{ lib, stdenv, cmake, extra-cmake-modules, plasma-framework, kwindowsystem, redshift, fetchFromGitHub, fetchpatch, }:
 
 let version = "1.0.18"; in
 
@@ -13,6 +13,17 @@ stdenv.mkDerivation {
     sha256 = "122nnbafa596rxdxlfshxk45lzch8c9342bzj7kzrsjkjg0xr9pq";
   };
 
+  patches = [
+    # This patch fetches from out-of-source repo because the GitHub copy is frozen,
+    #     the active fork is now on invent.kde.org. Remove this patch when a new version is released and src is updated
+    # Redshift version >= 1.12 requires the -P option to clear the existing effects before applying shading.
+    #     Without it scrolling makes the screen gets darker and darker until it is impossible to see anything.
+    (fetchpatch {
+      url = "https://invent.kde.org/plasma/plasma-redshift-control/-/commit/898c3a4cfc6c317915f1e664078d8606497c4049.patch";
+      sha256 =  "0b6pa3fcj698mgqnc85jbbmcl3qpf418mh06qgsd3c4v237my0nv";
+    })
+  ];
+
   patchPhase = ''
     substituteInPlace package/contents/ui/main.qml \
       --replace "redshiftCommand: 'redshift'" \