forgotten commit

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76924 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Resolve ambiguity in multiple inheritance of function GetPropertyByLabel in wxPGPage.

In wxPropertyGridPage class derived from wxPropertyGridPageState and wxPropertyGridInterface, function GetPropertyByLabel is inherited from both base classes.
To resolve this ambiguity, function defined in wxPGInterface is introduced in wxPGPage through 'using-declaration'.
(This is a temporary fix and finally GetPropertyByLabel function should be removed from wxPropertyGridPageState.)

See #15251.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76925 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775