Add filtering functionality to the symbols list (#8790)
- Added a filter edit box to the speech symbols dialog.
- Converted the list control to a list control with the `wx.LC_VIRTUAL` style. This provides a major performance boost this gives when loading the dialog for the first time, as well as when filtering.
- Added some functionality to `gui.nvdaControls.AutoWidthColumnListCtrl` to support getting item text from a data storage without the requirement of subclassing the list control. It is now also possible to forcefully send a `wx.EVT_LIST_ITEM_FOCUSED` to the control
