Don't reload records in system tests

As mentioned in commits like a586ba806, a7664ad81, 006128da5, b41fbfa52
and c480cdd91, accessing the database after starting the browser with
the `visit` method sometimes results in database corruption and failing
tests on our CI due to the process running the test accessing the
database after the process running the browser has started.

For example, one of these tests has recently failed on our CI:

```
3) Users Create a level 3 user with email from scratch
   Failure/Error: expect(user.reload).to be_confirmed
     expected `#<User id: 2060, email: "pepe@gmail.com", created_at:
     "2025-03-12 19:51:03.688867000 +0100", updated_...d_debates: true,
     recommended_proposals: true, subscriptions_token: nil,
     registering_from_web: false>.confirmed?` to be truthy, got false
```

IMHO this is also a bad practice for system tests, since these tests
should be checking what users experience.

So we're modifying the tests to check the results of users interaction
from the point of view of the users. For example, instead of checking
that a user is now level 3 verified in the database, we're checking that
the user interface states that the user is level 3 verified.

Note we're adding an offset when editing the map marker by clicking on
`map-location` with `.click(x: 30, y: 30)`. This way we make sure that
both the latitude and longitude change from the original values; we used
to clicking in the middle (no offset), which didn't change the longitude
and changed the latitude just by coincidence.

Also note we aren't changing tests with the `:no_js` tag, since these
tests don't run a real browser in a separate process. In the future, we
should also change most of these tests so they don't access the database
and they use a real browser.

spec/shared/system/mappable.rb

@@ -193,21 +193,35 @@ shared_examples "mappable" do |mappable_factory_name, mappable_association_name,
     end
 
     scenario "Should edit default values from map on #{mappable_factory_name} edit page" do
+      original_longitude = map_location.longitude
+      original_latitude = map_location.latitude
+
       do_login_for mappable.author, management: management
 
       visit send(mappable_edit_path, id: mappable.id)
-      find(".map-location").click
+      find(".map-location").click(x: 30, y: 30)
+
+      new_latitude = find_field(
+        "#{mappable_factory_name}_map_location_attributes_latitude", type: :hidden
+      ).value
+      new_longitude = find_field(
+        "#{mappable_factory_name}_map_location_attributes_longitude", type: :hidden
+      ).value
+
       click_button "Save changes"
 
       expect(page).not_to have_button "Save changes"
-      mappable.reload
-
-      expect(page).to have_css(".map-location")
-      expect(page).not_to have_css ".map-location[data-marker-latitude='#{map_location.latitude}']"
-      expect(page).to have_css ".map-location[data-marker-latitude='#{mappable.map_location.latitude}']"
+      expect(page).to have_css ".map-location"
+      expect(page).to have_css ".map-location[data-marker-latitude='#{new_latitude}']"
+      expect(page).to have_css ".map-location[data-marker-longitude='#{new_longitude}']"
+      expect(page).not_to have_css ".map-location[data-marker-latitude='#{original_latitude}']"
+      expect(page).not_to have_css ".map-location[data-marker-longitude='#{original_longitude}']"
     end
 
     scenario "Should edit mappable on #{mappable_factory_name} without change map" do
+      original_longitude = map_location.longitude
+      original_latitude = map_location.latitude
+
       do_login_for mappable.author, management: management
 
       visit send(mappable_edit_path, id: mappable.id)
@@ -215,11 +229,9 @@ shared_examples "mappable" do |mappable_factory_name, mappable_association_name,
       click_button "Save changes"
 
       expect(page).not_to have_button "Save changes"
-      mappable.reload
-
-      expect(page).to have_css(".map-location")
-      expect(page).to have_css ".map-location[data-marker-latitude='#{map_location.latitude}']"
-      expect(page).to have_css ".map-location[data-marker-latitude='#{mappable.map_location.latitude}']"
+      expect(page).to have_css ".map-location"
+      expect(page).to have_css ".map-location[data-marker-latitude='#{original_latitude}']"
+      expect(page).to have_css ".map-location[data-marker-longitude='#{original_longitude}']"
     end
 
     scenario "Can not display map on #{mappable_factory_name} edit when remove map marker" do