artists: rename is_active flag to is_deleted.

Rename is_active to is_deleted. This is for better consistency with
other models, and to reduce confusion over what "active" means for
artists. Sometimes users think active is for whether the artist is
actively producing work.

test/unit/artist_test.rb

@@ -191,7 +191,7 @@ class ArtistTest < ActiveSupport::TestCase
     end
 
     should "hide deleted artists" do
-      FactoryBot.create(:artist, :name => "warhol", :url_string => "http://warhol.com/a/image.jpg", :is_active => false)
+      create(:artist, name: "warhol", url_string: "http://warhol.com/a/image.jpg", is_deleted: true)
       assert_artist_not_found("http://warhol.com/a/image.jpg")
     end
 
@@ -512,7 +512,7 @@ class ArtistTest < ActiveSupport::TestCase
     context "that is deleted" do
       setup do
         @artist = create(:artist, url_string: "https://google.com")
-        @artist.update_attribute(:is_active, false)
+        @artist.update_attribute(:is_deleted, true)
         @artist.reload
       end
 

test/unit/artist_url_test.rb

@@ -191,12 +191,12 @@ class ArtistUrlTest < ActiveSupport::TestCase
       subject { ArtistUrl }
 
       should "work" do
-        @bkub = FactoryBot.create(:artist, name: "bkub", is_active: true, url_string: "https://bkub.com")
-        @masao = FactoryBot.create(:artist, name: "masao", is_active: false, url_string: "-https://masao.com")
+        @bkub = create(:artist, name: "bkub", url_string: "https://bkub.com")
+        @masao = create(:artist, name: "masao", url_string: "-https://masao.com")
         @bkub_url = @bkub.urls.first
         @masao_url = @masao.urls.first
 
-        assert_search_equals([@bkub_url], is_active: true)
+        assert_search_equals([@bkub_url], is_deleted: false)
         assert_search_equals([@bkub_url], artist: { name: "bkub" })
 
         assert_search_equals([@bkub_url], url_matches: "*bkub*")