Remove backwards compat code from IAccessibleHandler (#12232)
removes code marked as deprecated in #10934
PR #10934 refactored IAccessibleHandler into a package. This necessitated keeping some unused imports but marking them as deprecated. Also various parts of NVDA relied on the fact that IAccessibleHandler star imported all variables from IAccessible and IAccessible2 COM interfaces.
Unused imports are removed from IAccessibleHandler
NVDA's source has been modified to use IAccessible2 names from the COM interface rather than from IAccessibleHandler.
