Do not crash on boot if geos is not installed

Gemfile

@@ -25,7 +25,6 @@ gem 'devise' # Gestion des comptes utilisateurs
 gem 'devise-async'
 gem 'discard'
 gem 'dotenv-rails', require: 'dotenv/rails-now' # dotenv should always be loaded before rails
-gem 'ffi-geos'
 gem 'flipper'
 gem 'flipper-active_record'
 gem 'flipper-ui'

Gemfile.lock

@@ -215,8 +215,6 @@ GEM
     faraday (0.15.4)
       multipart-post (>= 1.2, < 3)
     ffi (1.12.2)
-    ffi-geos (2.1.0)
-      ffi (>= 1.0.0)
     flipper (0.17.2)
     flipper-active_record (0.17.2)
       activerecord (>= 4.2, < 7)
@@ -753,7 +751,6 @@ DEPENDENCIES
   discard
   dotenv-rails
   factory_bot
-  ffi-geos
   flipper
   flipper-active_record
   flipper-ui

app/models/geo_area.rb

@@ -55,13 +55,13 @@ class GeoArea < ApplicationRecord
   end
 
   def area
-    if polygon?
+    if polygon? && RGeo::Geos.supported?
       rgeo_geometry.area.round(1)
     end
   end
 
   def length
-    if line?
+    if line? && RGeo::Geos.supported?
       rgeo_geometry.length.round(1)
     end
   end