Remove completely turned on FF

flag=allow_lti_tools_editor_button_placement_without_icon
closes INTEROP-8484

Test plan:
- Create LTI tool with editor_button placement, with no icon_url at the
  top level or in the editor button placement.
- in the RCE, open the tools and make sure the generated icon shows up
  for the tool.

[fsc-max-nodes=18]
[fsc-timeout=40]

Change-Id: Ib5b62e2e6a93b20fb26ed3eb08dc377b871ec0fd
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/347025
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Tucker Mcknight <tmcknight@instructure.com>
QA-Review: Tucker Mcknight <tmcknight@instructure.com>
Product-Review: Evan Battaglia <ebattaglia@instructure.com>

app/models/context_external_tool.rb

@@ -836,10 +836,6 @@ class ContextExternalTool < ActiveRecord::Base
       settings.delete(type) unless extension_setting(type, :url)
     end
 
-    unless root_account.feature_enabled?(:allow_lti_tools_editor_button_placement_without_icon)
-      settings.delete(:editor_button) unless editor_button(:icon_url) || editor_button(:canvas_icon_class)
-    end
-
     sync_placements!(Lti::ResourcePlacement::PLACEMENTS.select { |type| settings[type] }.map(&:to_s))
     true
   end

config/feature_flags/interop_release_flags.yml

@@ -20,24 +20,6 @@ ags_scores_multiple_files:
   environments:
     development:
       state: on
-allow_lti_tools_editor_button_placement_without_icon:
-  state: hidden
-  applies_to: RootAccount
-  display_name: Allow LTI tools to have an editor button icon without placement (use default tool icon)
-  description: |-
-    When disabled, new or updated ContextExternalTool installations (including
-    LTI 1.3 tools updated automatically due to updates to their developer keys)
-    will have their editor_button placement removed if there is no icon_url or
-    canvas_icon_class provided in the settings (legacy behavior). When enabled,
-    the placement is not removed, so tools without icons will show a default
-    icon (with a color / letter based on tool name and tool/developer key ID).
-  environments:
-    development:
-      state: allowed_on
-    test:
-      state: allowed_on
-    ci:
-      state: allowed_on
 api_auth_error_updates:
   state: hidden
   display_name: Updates to JSON API auth error HTTP code and JSON status field

spec/models/context_external_tool_spec.rb

@@ -2572,20 +2572,6 @@ describe ContextExternalTool do
       expect(tool.editor_button).not_to be_nil
     end
 
-    context "when allow_lti_tools_editor_button_placement_without_icon FF is disabled" do
-      let(:ff) { :allow_lti_tools_editor_button_placement_without_icon }
-
-      before { @root_account.disable_feature! ff }
-      after { @root_account.enable_feature! ff }
-
-      it "deletes the editor_button if icon_url is not present" do
-        tool = new_external_tool
-        tool.settings = { editor_button: { url: "http://www.example.com" } }
-        tool.save
-        expect(tool.editor_button).to be_nil
-      end
-    end
-
     it "sets user_navigation if navigation configured" do
       tool = new_external_tool
       tool.settings = { user_navigation: { url: "http://www.example.com" } }