[Spreadsheet] Remove alias from dynamic properties on removeRows/Columns

When removing a row in a spreadsheet which has an assigned alias, the
alias will not be removed from the list of dynamic properties.

This makes it impossible to create a new alias which uses the same name
even if the original was removed (using removeRows/removeColumns)

Fixes #4492

src/Mod/Spreadsheet/App/Sheet.cpp

@@ -1135,6 +1135,14 @@ void Sheet::insertColumns(int col, int count)
 
 void Sheet::removeColumns(int col, int count)
 {
+    // Remove aliases, if defined
+    for (auto address : cells.getColumns(col, count)) {
+        auto cell = getCell(address);
+        std::string aliasStr;
+        if (cell && cell->getAlias(aliasStr))
+            removeDynamicProperty(aliasStr.c_str());
+    }
+
     cells.removeColumns(col, count);
     updateColumnsOrRows(true,col,-count);
 }
@@ -1163,6 +1171,14 @@ void Sheet::insertRows(int row, int count)
 
 void Sheet::removeRows(int row, int count)
 {
+    // Remove aliases, if defined
+    for (auto address : cells.getRows(row, count)) {
+        auto cell = getCell(address);
+        std::string aliasStr;
+        if (cell && cell->getAlias(aliasStr))
+            removeDynamicProperty(aliasStr.c_str());
+    }
+
     cells.removeRows(row, count);
     updateColumnsOrRows(false,row,-count);
 }