fix mismatch of filename

[VaibhavNarayann]

Fixes #4021

Downloading a project with its default (unedited) name worked correctly, the zip filename matched. However, after renaming the project, downloading it still produced a zip file with the old/default name instead of the updated one.

fix:

In server/controllers/project.controller.js, changed the zip filename generation to use project.name instead of project.slug:

Testing

-Downloaded a project with its default name, filename matched, as before.
-Renamed the project, then downloaded it, zip filename now correctly reflects the updated name.

I have verified that this pull request:

• has no linting errors (npm run lint)
• has no test errors (npm run test)
• has no typecheck errors (npm run typecheck)
• is from a uniquely-named feature branch and is up to date with the develop branch.
• is descriptively named and links to an issue number, i.e. Fixes #123
• meets the standards outlined in the accessibility guidelines