[🚀 Feature]: Grid properly matches enable download support #11658
Description
Feature and motivation
This is an extension of #11656 but I wanted to separate it out.
We know we want the Grid to set whether it allows downloads. Right now we're doing a flag where we have users specify the directory. If we are creating that directory for users, that won't be necessary. We can either keep the flag and change it to --enable-downloads or we can do whatever we do now by requiring a match of se:enableDownloads capability. I kind of like the latter approach because if a user requests a session with downloads enabled, but the Hub doesn't find a node with it turned on, it would be nice to get a clear error message that this is the case.
Usage example
backend implementation