Notification bar failing on some older notifications when Group or GroupContent is missing

Problem

Notification box is crashing with this error:

Error: Call to a member function getGroupContentType() on null in /app/html/profiles/contrib/social/modules/social_features/social_activity/social_activity.tokens.inc on line 81 #0 [internal function]: social_activity_tokens('message', Array, Array, Array, Object(Drupal\Core\Render\BubbleableMetadata))
#1 /app/html/core/lib/Drupal/Core/Extension/ModuleHandler.php(403): call_user_func_array('social_activity...', Array)
#2 /app/html/core/lib/Drupal/Core/Utility/Token.php(304): Drupal\Core\Extension\ModuleHandler->invokeAll('tokens', Array)
#3 /app/html/core/lib/Drupal/Core/Utility/Token.php(196): Drupal\Core\Utility\Token->generate('message', Array, Array, Array, Object(Drupal\Core\Render\BubbleableMetadata))
#4 /app/html/profiles/contrib/social/modules/custom/activity_creator/src/ActivityFactory.php(507): Drupal\Core\Utility\Token->replace('<p><a href="[me...', Array, Array)
#5 /app/html/modules/contrib/social_renamer/src/ActivityFactory.php(89): Drupal\activity_creator\ActivityFactory->processTokens(Array, false, Object(Drupal\message\Entity\Message))
#6 /app/html/profiles/contrib/social/modules/custom/activity_creator/activity_creator.module(218): Drupal\social_renamer\ActivityFactory->getMessageText(Object(Drupal\message\Entity\Message))
#7 [internal function]: activity_creator_entity_view(Array, Object(Drupal\activity_creator\Entity\Activity), Object(Drupal\Core\Entity\Entity\EntityViewDisplay), 'notification')

This most likely happens when the group content or group is removed but the activity item/message is still there.

Solution

Make the token handling more defensive.

Instead of just calling methods on the Entity object we should check if Entity is found before doing that.