Extract component to render a date range

Note we're using the `call` method (which is equivalent to adding an ERB
file) because we were getting an error calling `render` from the `dates`
method:

```
ActionView::Base#lookup_context delegated to
view_renderer.lookup_context, but view_renderer is nil:
```

It might be because we aren't rendering the
`Adming::Budgets::DurationComponent` but just calling one method, and so
there's no view context in this case.

app/components/admin/budgets/duration_component.rb

@@ -6,7 +6,7 @@ class Admin::Budgets::DurationComponent < ApplicationComponent
   end
 
   def dates
-    safe_join([formatted_start_date, "-", formatted_end_date], " ")
+    Admin::DateRangeComponent.new(start_time, end_time).call
   end
 
   def duration
@@ -15,15 +15,11 @@ class Admin::Budgets::DurationComponent < ApplicationComponent
 
   private
 
-    def formatted_start_date
-      formatted_date(durable.starts_at) if durable.starts_at.present?
+    def start_time
+      durable.starts_at
     end
 
-    def formatted_end_date
-      formatted_date(durable.ends_at - 1.second) if durable.ends_at.present?
-    end
-
-    def formatted_date(time)
-      time_tag(time, format: :short_datetime)
+    def end_time
+      durable.ends_at - 1.second if durable.ends_at.present?
     end
 end

app/components/admin/date_range_component.rb

@@ -0,0 +1,26 @@
+class Admin::DateRangeComponent < ApplicationComponent
+  attr_reader :start_time, :end_time
+
+  def initialize(start_time, end_time)
+    @start_time = start_time
+    @end_time = end_time
+  end
+
+  def call
+    safe_join([formatted_start_time, "-", formatted_end_time], " ")
+  end
+
+  private
+
+    def formatted_start_time
+      formatted_date(start_time) if start_time.present?
+    end
+
+    def formatted_end_time
+      formatted_date(end_time) if end_time.present?
+    end
+
+    def formatted_date(time)
+      time_tag(time, format: :short_datetime)
+    end
+end