fix: drop WhatsApp incoming messages from blocked contacts (#14061)

## Linear ticket

https://linear.app/chatwoot/issue/CW-6839/blocked-contact-can-still-send-messages-to-whatsapp-inbox

## Description

Drop WhatsApp incoming messages  from blocked contacts

## Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)

## How Has This Been Tested?

- Incoming messages for blocked contacts 

## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/services/whatsapp/incoming_message_base_service.rb

@@ -37,6 +37,7 @@ class Whatsapp::IncomingMessageBaseService
 
     set_contact
     return unless @contact
+    return if @contact.blocked? && !outgoing_echo
 
     ActiveRecord::Base.transaction do
       set_conversation