Ensure pub get is ran for all packages for flutter customer tests (#9270)

Author: kenzieschmoll

tool/flutter_customer_tests/setup.sh

@@ -18,7 +18,7 @@ export DEVTOOLS_TOOL_FLUTTER_FROM_PATH=true
 cd tool
 flutter pub get
 
-dt pub-get --upgrade
-dt generate-code --no-pub-get
+# This will run `dt pub-get --upgrade` before generating code with build_runner.
+dt generate-code --upgrade
 
 cd ..

tool/lib/commands/generate_code.dart

@@ -67,7 +67,7 @@ class GenerateCodeCommand extends Command {
     final upgrade = argResults![_upgradeFlag] as bool;
     if (pubGet) {
       await processManager.runProcess(
-        CliCommand.tool(['pub-get', '--only-main', if (upgrade) '--upgrade']),
+        CliCommand.tool(['pub-get', if (upgrade) '--upgrade']),
       );
     }