Keyboard accessibility of Shift+PageUp and Shift+PageDown not aligned with ARIA authoring practices guide

[balajis-qb]

Describe the bug
Shift+PageUp and Shift+PageDown keyboard shortcuts are not aligned with the W3C WAI-ARIA. Currently, Shift+PageUp is doing the same as the PageUp shortcut functionality and Shift+PageDown is doing the same as the PageDown shortcut functionality.

Date Picker Pattern

To Reproduce
Steps to reproduce the behavior:

1. Open the calendar
2. Move the focus to the calendar
3. Press Shift + PageUp or Shift + PageDown

Expected behavior

• Shift + PageUp should change the grid of dates to the same month in the previous year.
• Shift + PageDown should change the grid of dates to the same month in the next year.