Custom Dropdown - prevent unwanted option change on mouse wheel scrool

[krzychu124]

Fixes #1379

• CustomDropDown component for custom handling of the mouse wheel behavior over closed dropdown control,
• swapped vanilla control with custom to prevent unwanted changing selected dropdown option while scrolling the page - the reason why some users reported changing language to Arabic
• Besides the change in mouse wheel behavior on closed dropdown, it looks and works exactly like before (I've had to maually setup the control)

Build ZIP

[krzychu124]

I've added fix for memory leak and reduced number of instances created since for Dropdown the scrollbar stored under listScrollbar property is used as a template to generate a clone of scrollbar for popup window with options, so we can safely share a single instance across all components where needed, but needs to be destroyed manually between loading scenes, and it cannot be attached to component tree for automated lifecycle managment because layout breaks (attached component takes up the space...), hence why such weird construct (template is destroyed with first destroyed dropdown). 😕
I'll figure out better way of handling such case, since I saw more usecases but for now it works good enough for our needs.