granted: support fish shell (#6549)

Due to fish being a non-POSIX shell, granted provides a separate wrapper
to be used by fish.

tests/modules/programs/granted/default.nix

@@ -1,4 +1,6 @@
 {
-  granted-integration-enabled = ./integration-enabled.nix;
-  granted-integration-disabled = ./integration-disabled.nix;
+  granted-zsh-integration-enabled = ./zsh-integration-enabled.nix;
+  granted-zsh-integration-disabled = ./zsh-integration-disabled.nix;
+  granted-fish-integration-enabled = ./fish-integration-enabled.nix;
+  granted-fish-integration-disabled = ./fish-integration-disabled.nix;
 }

tests/modules/programs/granted/fish-integration-disabled.nix

@@ -0,0 +1,11 @@
+{
+  programs = {
+    granted.enable = true;
+    granted.enableFishIntegration = false;
+    fish.enable = true;
+  };
+
+  nmt.script = ''
+    assertPathNotExists home-files/.config/fish/functions/assume.fish
+  '';
+}

tests/modules/programs/granted/fish-integration-enabled.nix

@@ -0,0 +1,10 @@
+{
+  programs = {
+    granted.enable = true;
+    fish.enable = true;
+  };
+
+  nmt.script = ''
+    assertFileExists home-files/.config/fish/functions/assume.fish
+  '';
+}