Command length is limited to 255 characters, but AUTH JWT can be much larger

[chad-earthscope]

Spec includes: "Maximum length of the command line is 255 characters" with no exception for AUTH.

The AUTH JWT <jtw> command will likely easily include more than 255 "characters". A JWT header and signature alone can reach that limit.

Suggested fix: document an exception for an AUTH JWT command, which can likely be 2-4 KB