EchoModelFormatter extends EchoEventFormatter
EchoModelFormatter extends EchoEventFormatter

There was no point in letting it extend EchoFlyoutFormatter instead
of the base EchoEventFormatter. The only things in EchoFlyoutFormatter
are formatModel & getIconURL, both of which aren't being called.

Change-Id: I89511530a41976974f4d51d55379a617dfe503ec

wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo,wikimedia/mediawiki-extensions-Echo