Feat: Manage conversation for tweets based on the tweet flag (#3353)

Add tweet conversation only if tweets are enabled.

Fixes #1961

db/migrate/20211109143122_add_tweet_enabled_flag_to_twitter_channel.rb

@@ -0,0 +1,5 @@
+class AddTweetEnabledFlagToTwitterChannel < ActiveRecord::Migration[6.1]
+  def change
+    add_column :channel_twitter_profiles, :tweets_enabled, :boolean, default: true
+  end
+end