Update old usages of investments JSON data

We aren't using these properties since commit 3fa3c90db. An old test was
failing when checking for Axe accessibility issues because of this.

app/assets/javascripts/map.js

@@ -193,7 +193,6 @@
 
           if (App.Map.validCoordinates(coordinates)) {
             marker = createMarker(coordinates.lat, coordinates.long, coordinates.title);
-            marker.options.id = coordinates.investment_id;
             marker.bindPopup(App.Map.getPopupContent(coordinates));
           }
         });

app/models/map_location.rb

@@ -16,15 +16,6 @@ class MapLocation < ApplicationRecord
     mappable&.title
   end
 
-  def json_data
-    {
-      investment_id: investment_id,
-      proposal_id: proposal_id,
-      lat: latitude,
-      long: longitude
-    }
-  end
-
   def self.from_heading(heading)
     new(
       zoom: Budget::Heading::OSM_DISTRICT_LEVEL_ZOOM,

spec/system/budgets/budgets_spec.rb

@@ -305,9 +305,8 @@ describe "Budgets" do
         {
           lat: map_location[:latitude],
           long: map_location[:longitude],
-          investment_title: investment.title,
-          investment_id: investment.id,
-          budget_id: budget.id
+          title: investment.title,
+          link: "/budgets/#{budget.id}/investments/#{investment.id}"
         }
       end
 
@@ -316,7 +315,8 @@ describe "Budgets" do
       visit budgets_path
 
       within ".map-location" do
-        expect(page).to have_css(".map-icon", count: 1, visible: :all)
+        expect(page).to have_css ".map-icon", count: 1, visible: :all
+        expect(page).to have_css ".map-icon[aria-label='#{investment.title}']", visible: :all
       end
     end