Added length cap to sketch name

[siddhant1]

I have verified that this pull request:

• [x ] has no linting errors (npm run lint)
• [ x] is from a uniquely-named feature branch and has been rebased on top of the latest master. (If I was asked to make more changes, I have made sure to rebase onto master then too)
• [x ] is descriptively named and links to an issue number, i.e. Fixes #123

ref #568 (comment)

[catarak]

i think this is a great start and i can merge this in as it is now. however, i wonder if this should also be included server-side? someone could just delete the maximum length in the html and save the project.

[catarak]

i'm going to merge and leave #568 open.