refactor(backend): change naming of function names to avoid the is_ prefix

Following Credo.Check.Readability.PredicateFunctionNames check

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/service/export/common.ex

@@ -16,7 +16,7 @@ defmodule Mobilizon.Service.Export.Common do
   def fetch_actor_event_feed(name, limit) do
     case Actors.get_actor_by_name(name) do
       %Actor{} = actor ->
-        if Actor.is_public_visibility?(actor) do
+        if Actor.public_visibility?(actor) do
           %Page{elements: events} = Events.list_public_upcoming_events_for_actor(actor, 1, limit)
           %Page{elements: posts} = Posts.get_public_posts_for_group(actor, 1, limit)
           {:ok, actor, events, posts}

lib/service/export/feed.ex

@@ -265,7 +265,7 @@ defmodule Mobilizon.Service.Export.Feed do
   end
 
   defp clear_actor_feed(%Actor{preferred_username: preferred_username} = actor) do
-    if Actor.is_public_visibility?(actor) do
+    if Actor.public_visibility?(actor) do
       Cachex.del(:feed, "actor_#{preferred_username}")
     end
   end

lib/service/export/icalendar.ex

@@ -216,7 +216,7 @@ defmodule Mobilizon.Service.Export.ICalendar do
   end
 
   defp clear_actor_feed(%Actor{preferred_username: preferred_username} = actor) do
-    if Actor.is_public_visibility?(actor) do
+    if Actor.public_visibility?(actor) do
       Cachex.del(:ics, "actor_#{preferred_username}")
     end
   end