[v3] Update and fix runtime JS API (#3295)

* Cleanup bundled runtime entry point

* Fix JS representation of Screen struct

* Expose IsFocused method in Window interface

* Update JS window API

* Fix cleanup of WML listeners

* Bundle runtime as ES module

* Update runtime dependencies

* Update runtime types and events

* Update bundled runtime

* Update changelog

---------

Co-authored-by: Lea Anthony <lea.anthony@gmail.com>

v3/plugins/experimental/server/window.go

@@ -102,6 +102,10 @@ func (w Window) Hide() application.Window {
 	return w
 }
 
+func (w Window) IsFocused() bool {
+	return false
+}
+
 func (w Window) IsFullscreen() bool {
 	return false
 }