Use new Carbon Combobutton for scan button in Checker

[drjoho]

Mike Abbink
FYI
@jess

@alexandra
The checker can update with the new combo button. If I remember correctly this behaves that way. If not, then disregard.
https://react.carbondesignsystem.com/?path=/story/components-combobutton--default&globals=theme:white (edited)

Need to update carbon to get the new Combobutton and do significant testing due to the update.

[shunguoy]

triage: discuss w/ @drjoho on the priority of the issue and if it can be put in the current release.

[tombrunet]

[tombrunet]

The Scan and dropdown were initially implemented as two separate widgets. Carbon now has a Combobutton that may be able to use a more Carbon supported means of doing this.

[nam-singh]

Fixes in PR:#2137
Video WalkThrough:https://ibm-my.sharepoint.com/:v:/p/nam_singh/EYQoSBbppjpLoCrfMhgka_kBCBbDuW5R8mNMLC88LoSSgQ?nav=eyJyZWZlcnJhbEluZm8iOnsicmVmZXJyYWxBcHAiOiJPbmVEcml2ZUZvckJ1c2luZXNzIiwicmVmZXJyYWxBcHBQbGF0Zm9ybSI6IldlYiIsInJlZmVycmFsTW9kZSI6InZpZXciLCJyZWZlcnJhbFZpZXciOiJNeUZpbGVzTGlua0NvcHkifX0&e=YW29j4