Revert "electrum: fix build using upstream patch instead of own"

the proposed fix doesn't work on x86_64

This reverts commit 5058694c5b.

nixpatches/11-electrum-protobuf-fix.patch

@@ -0,0 +1,16 @@
+diff --git a/pkgs/applications/misc/electrum/default.nix b/pkgs/applications/misc/electrum/default.nix
+index 46ea57c6193..8f2768fac74 100644
+--- a/pkgs/applications/misc/electrum/default.nix
++++ b/pkgs/applications/misc/electrum/default.nix
+@@ -111,6 +111,11 @@ python3.pkgs.buildPythonApplication {
+     wrapQtApp $out/bin/electrum
+   '';
+ 
++  postPatch = ''
++    substituteInPlace contrib/requirements/requirements.txt \
++      --replace "protobuf>=3.12,<4" "protobuf>=3.12"
++  '';
++
+   checkInputs = with python3.pkgs; [ pytestCheckHook pyaes pycryptodomex ];
+ 
+   pytestFlagsArray = [ "electrum/tests" ];

nixpatches/list.nix

@@ -52,9 +52,6 @@ fetchpatch: [
     sha256 = "sha256-OczjlQcG7sTM/V9Y9VL/qdwaWPKfjAJsh3czqqhRQig=";
   })
 
-  # electrum: make compatible with protobuf 4+  (fixes electrum build)
-  (fetchpatch {
-    url = "https://github.com/NixOS/nixpkgs/pull/194112.diff";
-    sha256 = "sha256-Nmvu1U5HBT0YQ5aTE2gf0aaglq/1WpgacCbpqP7F+Qc=";
-  })
+  # fix electrum build: https://github.com/NixOS/nixpkgs/issues/193997
+  ./11-electrum-protobuf-fix.patch
 ]