Fix labels in color selection

We were using the same label for two elements, but the label was only
assigned to one of them.

spec/components/admin/geozones/form_component_spec.rb

@@ -0,0 +1,22 @@
+require "rails_helper"
+
+describe Admin::Geozones::FormComponent do
+  let(:geozone) { build(:geozone) }
+  let(:component) { Admin::Geozones::FormComponent.new(geozone) }
+
+  describe "color fields" do
+    it "renders two inputs sharing the same label" do
+      render_inline component
+
+      page.find(".color-inputs") do |color_inputs|
+        expect(color_inputs).to have_css "input", count: 2
+        expect(color_inputs).to have_css "label", count: 1
+
+        expect(color_inputs).to have_css "label#color_label[for=color_input]"
+        expect(color_inputs.all("input")[0][:"aria-labelledby"]).to eq "color_label"
+        expect(color_inputs.all("input")[0][:id]).not_to eq "color_input"
+        expect(color_inputs.all("input")[1][:id]).to eq "color_input"
+      end
+    end
+  end
+end