feat: Add inbox details endpoint (#5549)

This change targets the public API and is related to the Inbox with channel type API.
Exposes public inbox details under /public/api/v1/inboxes/{inbox_identifier}. This allows access to feature flags and business hours configured for the inbox.

ref: #5514

swagger/paths/index.yml

@@ -70,6 +70,14 @@
 
 # ------------  Public API routes  ------------#
 
+# Inbox
+
+/public/api/v1/inboxes/{inbox_identifier}:
+  parameters:
+    - $ref: '#/parameters/public_inbox_identifier'
+  get:
+    $ref: './public/inboxes/show.yml'
+
 # Contacts
 
 /public/api/v1/inboxes/{inbox_identifier}/contacts: