We're continuing to replace links with buttons, for the reasons
explained in commit 5311daadf.
Since we're using the admin action component, we can also simplify the
logic handling the confirmation message.
In order to avoid duplicate IDs when generating buttons to block the
same author more than once in a page, we're including the record dom_id
in the ID of the button to block an author.
Note that in proposal notifications we're writing the call to
render the component in the same line as the <div class="reply">
definition in order to be able to use the `:empty` selector when the
component renders nothing. No browser matches whitespace with the
`:empty` selector, so we can't add newline characters inside the tag. A
more elegant solution would be extracting the proposal notification
actions to a component and only rendering it if the moderation actions
component is rendered.
