Make remove marker label parameter optional

We were passing `nil` in some calls, which was confusing.

Since now we've got two optional parameters, we're using named
parameters.

app/components/budgets/map_component.html.erb

@@ -1,4 +1,4 @@
 <div class="map inline">
   <h2><%= t("budgets.index.map") %></h2>
-  <%= render_map(nil, "budgets", nil, coordinates) %>
+  <%= render_map(nil, "budgets", investments_coordinates: coordinates) %>
 </div>