chore: Reduce delta on ports to blockly-samples (#6886)

* Reduce usage of obsolete .keyCode property.
* Rename private properties/methods which violate eslint rules.
* Use arrays of bound events rather than individual properties.
* Improve typing info.
* Also fix O(n^2) recursive performance issue in theme's getComponentStyle function.
* And replace String(...) with '${...}' (smaller, faster).
* .toString() is considered harmful.

demos/blockfactory/analytics.js

@@ -171,8 +171,7 @@ BlocklyDevTools.Analytics.onExport = function(typeId, optMetadata) {
  */
 BlocklyDevTools.Analytics.onError = function(e) {
   // stub
-  this.LOG_TO_CONSOLE_ &&
-      console.log('Analytics.onError("' + e.toString() + '")');
+  this.LOG_TO_CONSOLE_ && console.log('Analytics.onError("' + e + '")');
 };
 
 /**