Remove special-case for diaspora-handle lookups in people controller.

Thss partly reverts a475d5fb62. The special case here was only ever used for the chat, which no longer exists.

app/controllers/people_controller.rb

@@ -126,16 +126,10 @@ class PeopleController < ApplicationController
 
   def find_person
     username = params[:username]
-    @person = if diaspora_id?(username)
-        Person.where({
-          diaspora_handle: username.downcase
-        }).first
-      else
-        Person.find_from_guid_or_username({
-          id: params[:id] || params[:person_id],
-          username: username
-        })
-      end
+    @person = Person.find_from_guid_or_username(
+      id:       params[:id] || params[:person_id],
+      username: username
+    )
 
     raise ActiveRecord::RecordNotFound if @person.nil?
     raise Diaspora::AccountClosed if @person.closed_account?

spec/controllers/people_controller_spec.rb

@@ -206,16 +206,6 @@ describe PeopleController, type: :controller do
       expect(assigns(:presenter).to_json).to eq(@presenter.to_json)
     end
 
-    it "404s if no person is found via diaspora handle" do
-      get :show, params: {username: "delicious@pod.net"}
-      expect(response.code).to eq("404")
-    end
-
-    it "finds a person via diaspora handle" do
-      get :show, params: {username: @person.diaspora_handle}
-      expect(assigns(:presenter).to_json).to eq(@presenter.to_json)
-    end
-
     it "redirects home for closed account" do
       @person = FactoryBot.create(:person, closed_account: true)
       get :show, params: {id: @person.to_param}