export the business_call_composer flag so g3 clients can consume

In order for g3 clients to consume flagged code, adding the is_exported
property is a necessary step.

Bug: 321156611
Test: manual
Change-Id: Ie38540758711b4d37d35713ad895b9df6cda8de3
diff --git a/flags/telecom_api_flags.aconfig b/flags/telecom_api_flags.aconfig
index c44bea4..ae28cc4 100644
--- a/flags/telecom_api_flags.aconfig
+++ b/flags/telecom_api_flags.aconfig
@@ -48,4 +48,5 @@
   namespace: "telecom"
   description: "Enables enriched calling features (e.g. Business name will show for a call)"
   bug: "311688497"
+  is_exported: true
 }