graphics/qgis-ltr: Fix build with gdal 3.13.0+
/wrkdirs/usr/ports/graphics/qgis-ltr/work/qgis-3.40.15/src/core/providers/ogr/qgsogrprovidermetadata.cpp:105:10: error: cannot initialize a variable of type 'char **' with an rvalue of type 'CSLConstList' (aka 'const char *const *')
105 | char **metadata = GDALGetMetadata( poDriver, nullptr );
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1 error generated.
/wrkdirs/usr/ports/graphics/qgis-ltr/work/qgis-3.40.15/src/core/providers/ogr/qgsogrproviderconnection.cpp:414:10: error: cannot initialize a variable of type 'char **' with an rvalue of type 'CSLConstList' (aka 'const char *const *')
414 | char **driverMetadata = GDALGetMetadata( hDriver, nullptr );
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~1 error generated.
Obtained from: https://github.com/qgis/QGIS/commit/ac1443a90bb295cfb179de969b07b885c64e6252
Approved by: portmgr (blanket)