Doesn't this add extra whitespace to the file?

It does, it would add two empty lines. This doesn't affect the SPEC file from what I've seen. There's a tradeoff, we either make the spec file more readable (there are some conventions I've seen, like double spaces between sections, which we don't do), or we make our template more readable.
There's also the possibility of using newline slurping -%> on the template. This should prevent both the if and forEach from creating empty lines, but lodash throws a SyntaxError when trying to use them. They might be a feature of ejs only.

Also, I think we might need another PR to make the whole spec file a little more readable and insert double spaces between sections which is a convention. It always bothered me that and ending curly brackets are not in the same line as the statement.

I think it also adds a line with trailing whitespace (where the forEach is), which is what I'm more worried about.

I figure out a way to deal with introducing empty lines. The code is still very readable.
By putting the closing tag on a new line, I'm able to better control readability and empty new lines. I'll use this technique in a new PR to make all .ejs files more readable in the future.