[eslint] Modify function linting for specs

Test Plan:
  - You should be able to use `function () {}` as a
    callback in a test.
  - You should be able to do the same without a function name
    warning showing

Change-Id: Ie6b7dcdc380f3b26bd6f3d8e0816f40016afc494
Reviewed-on: https://gerrit.instructure.com/98165
Tested-by: Jenkins
Reviewed-by: Jeremy Neander <jneander@instructure.com>
Product-Review: Clay Diffrient <cdiffrient@instructure.com>
QA-Review: Clay Diffrient <cdiffrient@instructure.com>

spec/javascripts/.eslintrc.json

@@ -9,5 +9,9 @@
         "ok": true,
         "sinon": true,
         "deepEqual": true
+    },
+    "rules": {
+      "func-names": ["off"],
+      "prefer-arrow-callback": ["off"]
     }
 }