feat(sales): validate PDF timezone parameter

lang/en/validation.php

@@ -37,6 +37,7 @@ return [
     'required_with' => 'The :attribute field is required when :values is present.',
     'required_without' => 'The :attribute field is required when :values is not present.',
     'string' => 'The :attribute must be a string.',
+    'timezone' => 'The timezone sent by the browser is invalid.',
     'unique' => 'The :attribute has already been taken.',
     'url' => 'The :attribute must be a valid URL.',
     'uuid' => 'The :attribute must be a valid UUID.',
@@ -52,6 +53,7 @@ return [
         'password_confirmation' => 'password confirmation',
         'telefono' => 'phone number',
         'tenant_codigo' => 'tenant',
+        'timezone' => 'timezone',
         'variant_id' => 'variant',
     ],
 ];