Skip installing "tool-mbctool" by default when upload target is invoked

It's requried since PlatformIO automatically installs uploaders

Author: valeros

platform.json

@@ -78,7 +78,6 @@
       "version": "~1.20600.0"
     }, 
     "tool-mbctool": {
-      "type": "uploader",
       "optional": true,
       "version": ">=2.0.0"
     },

platform.py

@@ -41,6 +41,7 @@ def configure_default_packages(self, variables, targets):
         if build_core == "mbcwb":
             self.packages['framework-arduinoespressif32']['optional'] = True
             self.packages['framework-arduino-mbcwb']['optional'] = False
+            self.packages['tool-mbctool']['type'] = "uploader"
             self.packages['tool-mbctool']['optional'] = False
 
         return PlatformBase.configure_default_packages(self, variables,