This PR fixes flaky test failures in the Instagram webhook specs that
were caused by Redis mutex lock conflicts when
tests ran in parallel.
### The Problem:
The InstagramEventsJob uses a Redis mutex with a key based on sender_id
and ig_account_id to prevent race
conditions. However, all test factories were using the same hardcoded
sender_id: 'Sender-id-1', causing multiple
test instances to compete for the same mutex lock when running in
parallel.
### The Solution:
- Updated all Instagram event factories to generate unique sender IDs
using SecureRandom.hex(4)
- Modified test stubs and expectations to work with dynamic sender IDs
instead of hardcoded values
- Ensured each test instance gets its own unique mutex key, eliminating
lock contention
When sending the message with audio, only the signed id of the file is sent.
In the back end check only the UploadedFile type.
The attachment has the default file type image, now it gets the content type from the signed id
Fixes: #5375
Co-authored-by: Sojan Jose <sojan@pepalo.com>
