bump back max allowed circular deps to 17

- somehow `madge` identifies circular in an order-dependent way,
  bump back to pre PR #1613 value.

Author: etpinard

tasks/test_syntax.js

@@ -177,7 +177,7 @@ function assertCircularDeps() {
         var logs = [];
 
         // see https://github.com/plotly/plotly.js/milestone/9
-        var MAX_ALLOWED_CIRCULAR_DEPS = 12;
+        var MAX_ALLOWED_CIRCULAR_DEPS = 17;
 
         if(circularDeps.length > MAX_ALLOWED_CIRCULAR_DEPS) {
             console.log(circularDeps.join('\n'));