Fix log message related to `pub global activate`  (#3187)

lib/src/global_packages.dart

diff --git a/lib/src/global_packages.dart b/lib/src/global_packages.dart
index 9c66bb8..578eca1 100644
--- a/lib/src/global_packages.dart
+++ b/lib/src/global_packages.dart
@@ -218,7 +218,7 @@
     if (sameVersions) {
       log.message('''
 The package ${dep.name} is already activated at newest available version.
-To recompile executables, first run `global deactivate ${dep.name}`.
+To recompile executables, first run `$topLevelProgram pub global deactivate ${dep.name}`.
 ''');
     } else {
       await result.showReport(SolveType.GET, cache);

test/global/activate/activate_hosted_twice_test.dart

diff --git a/test/global/activate/activate_hosted_twice_test.dart b/test/global/activate/activate_hosted_twice_test.dart
index 925a205..50ed807 100644
--- a/test/global/activate/activate_hosted_twice_test.dart
+++ b/test/global/activate/activate_hosted_twice_test.dart
@@ -39,7 +39,7 @@
 Package foo is currently active at version 1.0.0.
 Resolving dependencies...
 The package foo is already activated at newest available version.
-To recompile executables, first run `global deactivate foo`.
+To recompile executables, first run `dart pub global deactivate foo`.
 Activated foo 1.0.0.''');
 
     var pub = await pubRun(global: true, args: ['foo']);