chore: Add an API to find the contacts using contact inbox sourceId (#8012)

Fixes: https://linear.app/chatwoot/issue/CW-2578/search-by-facebook-id

app/controllers/api/v1/accounts/contact_inboxes_controller.rb

@@ -0,0 +1,21 @@
+class Api::V1::Accounts::ContactInboxesController < Api::V1::Accounts::BaseController
+  before_action :ensure_inbox
+
+  def filter
+    contact_inbox = @inbox.contact_inboxes.where(inbox_id: permitted_params[:inbox_id], source_id: permitted_params[:source_id])
+    return head :not_found if contact_inbox.empty?
+
+    @contact = contact_inbox.first.contact
+  end
+
+  private
+
+  def ensure_inbox
+    @inbox = Current.account.inboxes.find(permitted_params[:inbox_id])
+    authorize @inbox, :show?
+  end
+
+  def permitted_params
+    params.permit(:inbox_id, :source_id)
+  end
+end

app/views/api/v1/accounts/contact_inboxes/filter.json.jbuilder

@@ -0,0 +1 @@
+json.partial! 'api/v1/models/contact', formats: [:json], resource: @contact, with_contact_inboxes: true