Fix exception if mod metadata not fetched.

If the mod metadata can't be fetched, such as if running from the wrong directory, an exception will be thrown when checking for DLC. This is not an correct exception.
Check for this case and log a more useful message.

WorkshopToolCommon/Uploader.cs

@@ -75,7 +75,8 @@ public Uploader(WorkshopType type, string path, Options.UploadVerb options, stri
                 m_modId = WorkshopHelper.GetWorkshopIdFromMod(m_modPath);
 
             // Fill defaults before assigning user-defined ones
-            FillPropertiesFromPublished();
+            if (m_modId.Length > 0 && m_modId.GetIds()[0] != 0 && !FillPropertiesFromPublished())
+                MySandboxGame.Log.WriteLineWarning("Mod has a published ID, but unable to look up properties. This is wrong.");
 
             m_compile = options.Compile;
             m_dryrun = options.DryRun;
@@ -387,7 +388,7 @@ bool FillPropertiesFromPublished()
                 }
                 return false;
             }
-            return true;
+            return false;
         }
 
         ulong ParseOrGetWorkshopID(string idOrName)
@@ -413,7 +414,7 @@ ulong ParseOrGetWorkshopID(string idOrName)
         // Mod must be published for that to work.
         void ProcessDependencies(IEnumerable<string> deps, IEnumerable<string> add, IEnumerable<string> remove)
         {
-            var existingDeps = m_workshopItems[m_modId[0]].Dependencies.ToList();
+            var existingDeps = m_workshopItems.GetValueOrDefault(m_modId.FirstOrDefault())?.Dependencies.ToList() ?? new List<ulong>();
 
             // Check if the deps contains exactly one element, and that element is a 0 or "none",
             // if so, set the result to a list of a single ulong value of 0
@@ -468,7 +469,7 @@ bool CheckDependency(MyWorkshopItem item)
         void ProcessDLCs(IEnumerable<uint> dlcs, IEnumerable<uint> add, IEnumerable<uint> remove)
         {
 #if SE
-            var existingDeps = m_workshopItems[m_modId[0]].DLCs.ToList();
+            var existingDeps = m_workshopItems.GetValueOrDefault(m_modId.FirstOrDefault())?.DLCs.ToList() ?? new List<uint>();
             var explicitDeps = dlcs?.ToList();
             var depsToAdd = add?.ToList();
             var depsToRemove = remove?.ToList();