Only add the post format body classes when the post type supports post formats

[ocean90]

Same as #16224 and r17292 but this time for the body class.

get_post_format() already performs a post_type_supports() check and returns false as of r17429.

That's right, but it returns also false if get_the_terms is empty.

Ah, missed the else clause.

In [18651]:

Only add the post format body classes when the post type supports post formats. props ocean90. fixes #18228.