Add admin API for managing canonical e-mail blocks (#19067)

app/policies/canonical_email_block_policy.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+class CanonicalEmailBlockPolicy < ApplicationPolicy
+  def index?
+    role.can?(:manage_blocks)
+  end
+
+  def show?
+    role.can?(:manage_blocks)
+  end
+
+  def test?
+    role.can?(:manage_blocks)
+  end
+
+  def create?
+    role.can?(:manage_blocks)
+  end
+
+  def destroy?
+    role.can?(:manage_blocks)
+  end
+end