[1.8.x] Refs #24836 -- Reverted "Simplified the lazy CSRF token implementation in csrf context processor."

This reverts commit 8099d33b65 as it caused
a regression that cannot be solved without changing force_text() which has
a small risk of introducing regressions. This change will remain in master
along with an update to force_text().

tests/csrf_tests/test_context_processor.py

@@ -0,0 +1,15 @@
+import json
+
+from django.http import HttpRequest
+from django.template.context_processors import csrf
+from django.test import SimpleTestCase
+from django.utils.encoding import force_text
+
+
+class TestContextProcessor(SimpleTestCase):
+
+    def test_force_text_on_token(self):
+        request = HttpRequest()
+        request.META['CSRF_COOKIE'] = 'test-token'
+        token = csrf(request).get('csrf_token')
+        self.assertEqual(json.dumps(force_text(token)), '"test-token"')