pub global deactivate devtools before installing (#82491)
pub global deactivate devtools before installing (#82491)

* pub global deactivate devtools before installing
* upgrade devtools to latest
Hixie/flutter,tvolkert/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,tvolkert/flutter,Hixie/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,tvolkert/flutter