add flag for transactional CS changes

b/267234374 was merged to V without a flag to gate the new logic.
This CL gates all the changes in b/267234374 and updates 2 tests.

Fixes: 309541257
Bug: 267234374 (root bug)
Test: 2 modified tests
Change-Id: I26967870b19be3670248ea237ccd8198f624c079
diff --git a/flags/Android.bp b/flags/Android.bp
index 6fa147a..63a67ae 100644
--- a/flags/Android.bp
+++ b/flags/Android.bp
@@ -29,6 +29,7 @@
       "telecom_incallservice_flags.aconfig",
       "telecom_default_phone_account_flags.aconfig",
       "telecom_callaudioroutestatemachine_flags.aconfig",
+      "telecom_call_flags.aconfig",
       "telecom_calls_manager_flags.aconfig",
       "telecom_anomaly_report_flags.aconfig",
       "telecom_callaudiomodestatemachine_flags.aconfig",
diff --git a/flags/telecom_call_flags.aconfig b/flags/telecom_call_flags.aconfig
new file mode 100644
index 0000000..b5ea6a2
--- /dev/null
+++ b/flags/telecom_call_flags.aconfig
@@ -0,0 +1,8 @@
+package: "com.android.server.telecom.flags"
+
+flag {
+  name: "transactional_cs_verifier"
+  namespace: "telecom"
+  description: "verify connection service callbacks via a transaction"
+  bug: "309541257"
+}
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