Prevent showing 0x0 artwork when a recording doesn't have Seas/Ep.

I am not sure why this solution didn't occur to me earlier,

Basically, if the season input to the methods is 0, just order
the season results descending.  That way if the user has set
artwork (or any artwork has been set for anything > 1x01),
it'll be shown in higher priority than the 0x0 artwork.

The bug still exists (it's just inverted now, you'd get TV results
if you actually had TV and movies with the same legit inetref,
but this should affect far, far, far fewer people. Many/most users
will probably never see this inversion of the bug at all.

Refs #10408

mythtv/libs/libmythtv/metadataimagehelper.cpp

@@ -19,12 +19,20 @@ ArtworkMap GetArtwork(QString inetref,
     if (strict)
         querystring += "AND season = :SEASON;";
     else
-        querystring += "ORDER BY season = :SEASON DESC, season DESC;";
+    {
+        if (season > 0)
+        {
+            querystring += "ORDER BY season = :SEASON DESC, season DESC;";
+        }
+        else
+            querystring += "ORDER BY season DESC;";
+    }
 
     query.prepare(querystring);
 
     query.bindValue(":INETREF", inetref);
-    query.bindValue(":SEASON", season);
+    if (strict || season > 0)
+        query.bindValue(":SEASON", season);
 
     if (!query.exec())
     {