chore: stop building contributor tools

They should really be in a separate repo, but for now I'm preventing
them from being built.

package.json

@@ -26,11 +26,6 @@
     "curriculum",
     "tools/challenge-helper-scripts",
     "tools/challenge-parser",
-    "tools/contributor",
-    "tools/contributor/dashboard-app/client",
-    "tools/contributor/dashboard-app/server",
-    "tools/contributor/lib/",
-    "tools/contributor/one-off-scripts",
     "tools/crowdin",
     "tools/scripts/build",
     "tools/scripts/seed",