Merge pull request #20773 from sivanov-work:merge_vpl_source_unite

G-API: oneVPL (simplification) unite components in entire VPL source

* Unify components in VPLSource

* Revert back decode WRN & Add compile guard

* Address come comments

* Add source alias

* Apply comment for exception handling

modules/gapi/include/opencv2/gapi/streaming/onevpl/source.hpp

@@ -51,6 +51,8 @@ private:
 };
 } // namespace onevpl
 
+using GVPLSource = onevpl::GSource;
+
 template<class... Args>
 GAPI_EXPORTS_W cv::Ptr<IStreamSource> inline make_onevpl_src(Args&&... args)
 {