Remove backwards compat code from IAccessibleHandler

[lukaszgo1]

Link to issue number:

None, removes code marked as deprecated in #10934

Summary of the issue:

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.

Description of how this pull request fixes the issue:

• Unused imports are removed from IAccessibleHandler
• NVDA's source has been modified to use IAccessible2 names from the COM interface rather than from IAccessibleHandler.

Testing strategy:

Manual testing:
Ensured that NVDA still starts, and works in general. Spend about an hour browsing in Firefox without any apparent changes in behavior.

With git grep inspected all usages of IAccessibleHandler to make sure that nothing in NVDA's source relies on things star imported there any longer.

Known issues with pull request:

None known

Change log entry:

Section: Changes for developers:

• IAccessibleHandler no longer star imports everything from IAccessible and IA2 COM interfaces - please use them directly.

Code Review Checklist:

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• Pull Request description is up to date.
• Unit tests.
• System (end to end) tests.
• Manual tests.
• User Documentation.
• Change log entry.
• Context sensitive help for GUI changes.

[lukaszgo1]

cc @seanbudd

[seanbudd]

Thanks @lukaszgo1, looks good to me