Fix time_ago_with_tooltip for activity feed

Closes #4002

app/helpers/application_helper.rb

@@ -204,12 +204,16 @@ module ApplicationHelper
   # Returns an HTML-safe String
   def time_ago_with_tooltip(time, placement: 'top', html_class: 'time_ago', skip_js: false)
     element = content_tag :time, time.to_s,
-      class: "#{html_class} js-timeago",
+      class: "#{html_class} js-timeago js-timeago-pending",
       datetime: time.getutc.iso8601,
       title: time.in_time_zone.stamp('Aug 21, 2011 9:23pm'),
       data: { toggle: 'tooltip', placement: placement, container: 'body' }
 
-    element += javascript_tag "$('.js-timeago').last().timeago()" unless skip_js
+    unless skip_js
+      element << javascript_tag(
+        "$('.js-timeago-pending').removeClass('js-timeago-pending').timeago()"
+      )
+    end
 
     element
   end

spec/helpers/application_helper_spec.rb

@@ -263,11 +263,12 @@ describe ApplicationHelper do
     end
 
     it 'includes a default js-timeago class' do
-      expect(element.attr('class')).to eq 'time_ago js-timeago'
+      expect(element.attr('class')).to eq 'time_ago js-timeago js-timeago-pending'
     end
 
     it 'accepts a custom html_class' do
-      expect(element(html_class: 'custom_class').attr('class')).to eq 'custom_class js-timeago'
+      expect(element(html_class: 'custom_class').attr('class')).
+        to eq 'custom_class js-timeago js-timeago-pending'
     end
 
     it 'accepts a custom tooltip placement' do
@@ -278,7 +279,7 @@ describe ApplicationHelper do
       el = element.next_element
 
       expect(el.name).to eq 'script'
-      expect(el.text).to include "$('.js-timeago').last().timeago()"
+      expect(el.text).to include "$('.js-timeago-pending').removeClass('js-timeago-pending').timeago()"
     end
 
     it 'allows the script tag to be excluded' do