Allow disabling line highlighting on click in `PhabricatorSourceCodeView`

Summary:
There may be times when we don't want lines in some embeded source
code to be highlighted on click, this adds that functionality.

Also use the functionalty in `PasteEmbedView`

Test Plan:
- View paste, make sure everything works.
- Embed paste in comment, make sure everything works apart from click hl

Reviewers: epriestley

Reviewed By: epriestley

CC: Korvin, aran

Maniphest Tasks: T3881

Differential Revision: https://secure.phabricator.com/D7111