In my experience it's a positive sign to have an active Github profile or open source contributions, but it is not a negative sign if a candidate doesn't have one.
At higher levels (Principal, Distinguished) you often have to show external contributions to the industry, and some companies count open source towards this.
I can honestly say that my profile has been a huge benefit to my career, but that's more due to 20 years of open source contributions and a very customized (and automated) profile page.