Fixing A11y issues in combobox and scroll bar

[harshit7962]

Description

The following PR fixes Accessibility issue which occurs due to improper naming of nested controls of scroll bar and editable combo box. Additionally, it fixes the one's with datepicker.

Customer Impact

Customers using accessibility tools will find it easier to navigate with the help of narrator and other tools.

Regression

None

Testing

Local Build Pass Sample Application Testing

Risk

The name of scroll bar's repeat button is hard coded to up, down, left or right in the changes. Might need to verify if this conveys the message or do we need to be able to bind it based on its parent name.