Add space between external media video and card header

[Kristina Hoeppner]

When you have an image, the image has a bit of space to the block heading whereas "External media" does not. The latter is missing the card body class. "Embedded media" for internal video does have the class again.

see attachment

To replicate:

1. Add a photo to a page.
2. Add a YouTube video to the page via the "External media" block.
Expected result: Both media items have a bit of space to the block header.
Actual result: Only the image has the space. The YouTube video is right at the header line so it's hardly visible.

[Mahara Bot (dev-mahara)]

Patch for "master" branch: https://reviews.mahara.org/10327

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/10327
Committed: https://git.mahara.org/mahara/mahara/commit/1622bd2e02a302df961451459781e0ca662e2a02
Submitter: Robert Lyon (<email address hidden>)
Branch: master

commit 1622bd2e02a302df961451459781e0ca662e2a02
Author: Evonne <email address hidden>
Date: Tue Sep 10 15:28:54 2019 +1200

Bug 1843363 Add space between external media video and card header

Put in class card-body for external media video block to add the
space and be consistent with other blocks.

behatnotneeded

Change-Id: I164ecff8b2505a5f5e393ff623dff4512f296345