wxGUI: update Slovakia 3D precipitation voxel sample dataset URL (#1292)

gui/wxpython/gmodeler/g.gui.gmodeler.html

@@ -324,7 +324,7 @@ reusable workflow that may be run also by other users with different data.
 <!-- TODO: next line, which model? -->
 For example, this model can later be used to calculate the average precipitation
 for every administrative region in Slovakia using the <tt>precip</tt> raster data from
-<a href="https://grass.osgeo.org/uploads/grass/sampledata/slovakia3d_grass7.tar.gz">
+<a href="https://grass.osgeo.org/sampledata/slovakia3d_grass7.tar.gz">
 Slovakia precipitation dataset</a> and administration boundaries of Slovakia from 
 <a href="https://www.geoportal.sk/sk/zbgis_smd/na-stiahnutie/">Slovak Geoportal</a>
 (only with a few clicks).

gui/wxpython/startup/locdownload.py

@@ -72,7 +72,7 @@ LOCATIONS = [
     },
     {
         "label": "Slovakia 3D precipitation voxel data set",
-        "url": "https://grass.osgeo.org/uploads/grass/sampledata/slovakia3d_grass7.tar.gz",
+        "url": "https://grass.osgeo.org/sampledata/slovakia3d_grass7.tar.gz",
     },
     {
         "label": "Fire simulation sample data",