Use custom translations in components

In the `i18n_translation` initializer, we're overwriting the `t` helper
so calling it uses custom translations if they're available.

However, ViewComponent doesn't use the `t` helper but implements its own
`t` method. So, when calling the `t` method in a component, we weren't
using our implementation of the `t` helper, and so we weren't loading
custom translations.

Using the `t` helper in components solves the issue.

There was a test where we were directly testing a method in a component,
and that method uses the `t` helper. This caused an error when running
the test:

ViewComponent::Base::ViewContextCalledBeforeRenderError:
`#helpers` can't be used during initialization, as it depends on the
view context that only exists once a ViewComponent is passed to the
Rails render pipeline.

Using `render_inline` in the test and testing the generated HTML, as
recommended in the ViewComponent documentation, solves the issue.

spec/components/application_component_spec.rb

@@ -0,0 +1,21 @@
+require "rails_helper"
+
+describe ApplicationComponent do
+  it "uses custom translations if present" do
+    I18nContent.update([{ id: "shared.yes", values: { "value_en" => "Affirmative" }}])
+
+    component_class = Class.new(ApplicationComponent) do
+      def call
+        t("shared.yes")
+      end
+
+      def self.name
+        ""
+      end
+    end
+
+    render_inline component_class.new
+
+    expect(page).to be_rendered with: "<p>Affirmative</p>"
+  end
+end