This commit fixes an issue where clicking the default
"Take Action" option on a flag for a post doesn't always
end up with the post hidden.
This is because the "take_action" score bonus doesn’t take into account
the final score required to hide the post.
Especially with the `hide_post_sensitivity` site setting set to `low`
sensitivity, there is a likelihood the score needed to hide the post
won’t be reached.
Now, the default "Take Action" button has been changed to "Hide Post"
to reflect what is actually happening and the description has been
improved, and if "Take Action" is clicked we _always_ hide the post
regardless of score and sensitivity settings. This way the action reflects
expectations of the user.
