Add ability for admins to delete canonical email blocks (#16644)

* Add admin option to remove canonical email blocks from a deleted account

* Add tootctl canonical_email_blocks to inspect and remove canonical email blocks

lib/mastodon/canonical_email_blocks_cli.rb

@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require 'concurrent'
+require_relative '../../config/boot'
+require_relative '../../config/environment'
+require_relative 'cli_helper'
+
+module Mastodon
+  class CanonicalEmailBlocksCLI < Thor
+    include CLIHelper
+
+    def self.exit_on_failure?
+      true
+    end
+
+    desc 'find EMAIL', 'Find a given e-mail address in the canonical e-mail blocks'
+    long_desc <<-LONG_DESC
+      When suspending a local user, a hash of a "canonical" version of their e-mail
+      address is stored to prevent them from signing up again.
+
+      This command can be used to find whether a known email address is blocked,
+      and if so, which account it was attached to.
+    LONG_DESC
+    def find(email)
+      accts = CanonicalEmailBlock.find_blocks(email).map(&:reference_account).map(&:acct).to_a
+      if accts.empty?
+        say("#{email} is not blocked", :yellow)
+      else
+        accts.each do |acct|
+          say(acct, :white)
+        end
+      end
+    end
+
+    desc 'remove EMAIL', 'Remove a canonical e-mail block'
+    long_desc <<-LONG_DESC
+      When suspending a local user, a hash of a "canonical" version of their e-mail
+      address is stored to prevent them from signing up again.
+
+      This command allows removing a canonical email block.
+    LONG_DESC
+    def remove(email)
+      blocks = CanonicalEmailBlock.find_blocks(email)
+      if blocks.empty?
+        say("#{email} is not blocked", :yellow)
+      else
+        blocks.destroy_all
+        say("Removed canonical email block for #{email}", :green)
+      end
+    end
+
+    private
+
+    def color(processed, failed)
+      if !processed.zero? && failed.zero?
+        :green
+      elsif failed.zero?
+        :yellow
+      else
+        :red
+      end
+    end
+  end
+end