Wait for page load so we're not getting stale elements

while producing products. Basically an attempt to fix:
https://gitlab.com/gitlab-org/gitlab-qa/-/jobs/65016456

Selenium::WebDriver::Error::StaleElementReferenceError:
  stale element reference: element is not attached to the page document

in:

``` ruby
product :name do
  Page::Project::Settings::Repository.act do
    expand_protected_branches(&:last_branch_name)
  end
end
```

qa/qa/factory/resource/branch.rb

@@ -76,6 +76,11 @@ module QA
               end
 
               page.protect_branch
+
+              # Wait for page load, which resets the expanded sections
+              page.wait(reload: false) do
+                !page.has_content?('Collapse')
+              end
             end
           end
         end