Public function name misspelled

Since that is a controller method, and the .routing.yml file contains a _controller: '\Drupal\drealty\Controller\DrealtyConnectionEntityController::viewEntityCotroller' line, this can be either fixed or left as it is.

entity.drealty_connection.view_page:
  path: '/admin/drealty/connection/{drealty_connection}'
  defaults:
    _controller: '\Drupal\drealty\Controller\DrealtyConnectionEntityController::viewEntityCotroller'
    entity_type: 'drealty_class'
    _title_callback: '\Drupal\drealty\Controller\DrealtyConnectionEntityController::title'
  options:
    parameters:
      drealty_connection:
        type: 'entity:drealty_connection'
  requirements:
    _permission: 'administer drealty connections'

Other modules should not need to reference that method. Usually, they just need to reference the route name (entity.drealty_connection.view_page).

I'll create a patch once I get my development environment up and running. Unless someone else gets to it first.