refactor(tests): update completion tests to reflect code changes

Author: xHeaven

tests/Integration/Console/Commands/CompletionInstallCommandTest.php

@@ -44,7 +44,7 @@ public function install_with_invalid_shell(): void
         $this->console
             ->withoutPrompting()
             ->call('completion:install --shell=fish')
-            ->assertSee('Could not determine shell')
+            ->assertSee('Invalid argument `fish` for `shell` argument')
             ->assertError();
     }
 

tests/Integration/Console/Commands/CompletionShowCommandTest.php

@@ -36,7 +36,7 @@ public function show_with_invalid_shell(): void
         $this->console
             ->withoutPrompting()
             ->call('completion:show --shell=fish')
-            ->assertSee('Could not determine shell')
+            ->assertSee('Invalid argument `fish` for `shell` argument')
             ->assertError();
     }
 }

tests/Integration/Console/Commands/CompletionUninstallCommandTest.php

@@ -38,7 +38,7 @@ public function uninstall_with_invalid_shell(): void
         $this->console
             ->withoutPrompting()
             ->call('completion:uninstall --shell=fish')
-            ->assertSee('Could not determine shell')
+            ->assertSee('Invalid argument `fish` for `shell` argument')
             ->assertError();
     }