Celery task context sticks to the main transaction which is misleading

**Describe the bug**: ...

Celery task execution sticks to the main transaction of the django view. This is really misleading cause you may think that your view\endpoint works really slow, but in reality user already received response.


**Environment (please complete the following information)**
- OS: Linux (heroku)
- Python version: 3.11
- Framework and version [e.g. Django 2.1]: Django 5
- APM Server version:
- Agent version: elastic-apm = "^6.23.0"
- Celery celery = {extras = ["sqs"], version = "^5.5.1"}

**Additional context**
`elasticapm.contrib.django.middleware.TracingMiddleware` middleware in the beginning (first).
Celery task is called trough .apply_async or .delay() doesn't matter.

Any ideas why it may happen? I assume it should be displayed just like it was called and that's it, without internal context sticked to the main View\endpoint transaction.

Reproduce with Django 5, Python 3.11, elastic-apm 6.23.0, and Celery 5.5.1, placing elasticapm.contrib.django.middleware.TracingMiddleware first and invoking tasks through both .apply_async and .delay(). Compare the task and view transaction timing and context; done means the task is displayed independently after the view response rather than remaining attached to the main view transaction.

Written by the indexing model from the issue text.