Array to String conversion Notice in webform_submission_render

Problem
After update to webform 7.x-4.14 I found a php Notice was being always displayed after submit a webform.
Digging in the code I found the problem was in the way the function webform_submission_render is excluding components.

// Remove excluded components.
  if (is_array($excluded_components)) {
    foreach ($excluded_components as $cid) {
      unset($components[$cid]);
    }
    if (!empty($email['exclude_empty'])) {
      foreach ($submission->data as $cid => $data) {
        // Caution. Grids store their data in an array index by question key.
        if (implode($data) == '') {
          unset($components[$cid]);
        }
      }
    }
  }

When $data is a matrix, the implode will return an error (we only can implode strings not arrays).

Solution
Take into account the $data variable could be a multidimensional array. The previous module version code will work fine.

 // Remove excluded components.
  if (is_array($excluded_components)) {
    foreach ($excluded_components as $cid) {
      unset($components[$cid]);
    }
    if (!empty($email['exclude_empty'])) {
      foreach ($submission->data as $cid => $data) {
        // Caution. Grids store their data in an array index by question key.
        foreach ($data as $value) {
          if ($value != '') {
            // This component has a non-empty value. Continue the outer loop.
            continue 2;
          }
        }
        unset($components[$cid]);
      }
    }
  }

I know it's not the most efficient approach but I think we should roll back to the previous version to avoid problem and then think in a better way to do it.

There is another issue that maybe related but it was closed recently , #2601546: Improve "exclude_empty" processing.. The approach in that ticket is use implode, so the problem will still be there.