Restrict CSS selection to children anchor tags of a Review Request's menu bar items

Testing was only done on the review_export extension and all core menu functionality.

Checked other dropdown menus to see if their actions worked (Close -> Submitted, Close -> Discarded)
Tried the primary menu actions (actions with no dropdowns)

    a) View Diff

    b) Download Diff

    c) Review

    d) Ship It!
Tested the functionality on File Attachment actions:

    a) Update

    b) Delete

All Worked successfully.