mousai: move to pkgs/by-name

(cherry picked from commit a8e5c604cc)

pkgs/applications/audio/mousai/paths.patch

@@ -1,13 +0,0 @@
-diff --git a/src/backend/utils.py b/src/backend/utils.py
-index cebc009..0087c09 100644
---- a/src/backend/utils.py
-+++ b/src/backend/utils.py
-@@ -79,7 +79,7 @@ class Utils:
-     @staticmethod
-     def get_default_audio_sources():
-         pactl_output = subprocess.run(
--            ['/usr/bin/pactl', 'info'],
-+            ['@pactl@', 'info'],
-             stdout=subprocess.PIPE,
-             text=True
-         ).stdout.splitlines()

pkgs/top-level/all-packages.nix

@@ -32889,8 +32889,6 @@ with pkgs;
 
   motif = callPackage ../development/libraries/motif { };
 
-  mousai = callPackage ../applications/audio/mousai { };
-
   mozjpeg = callPackage ../applications/graphics/mozjpeg { };
 
   edgetx = libsForQt5.callPackage ../applications/misc/edgetx { };