Apply Dnd filter only calls with dnd only filter extra

1. Still apply Dnd call filter even if phone account has EXTRA_SKIP_CALL_FILTERING
, this is to make sure BluetoothInCallService works as intended when Dnd is on.

2. Create a provider interface for InComingCallFilterGraph for uni testing purpose.

Test: manual test works, dialer can receive this boolean in extra
Bug: 222333869
Change-Id: I9e65555d0524b213cb1ab2e9b89316f9638f80e9
diff --git a/flags/Android.bp b/flags/Android.bp
index 0e2071b..402826a 100644
--- a/flags/Android.bp
+++ b/flags/Android.bp
@@ -25,6 +25,7 @@
       "telecom_broadcast_flags.aconfig",
       "telecom_ringer_flag_declarations.aconfig",
       "telecom_api_flags.aconfig",
+      "telecom_call_filtering_flags.aconfig",
       "telecom_incallservice_flags.aconfig"
     ],
 }
diff --git a/flags/telecom_call_filtering_flags.aconfig b/flags/telecom_call_filtering_flags.aconfig
new file mode 100644
index 0000000..95e74ce
--- /dev/null
+++ b/flags/telecom_call_filtering_flags.aconfig
@@ -0,0 +1,8 @@
+package: "com.android.server.telecom.flags"
+
+flag {
+  name: "skip_filter_phone_account_perform_dnd_filter"
+  namespace: "telecom"
+  description: "Gates whether to still perform Dnd filter when phone account has skip_filter call extra."
+  bug: "222333869"
+}
\ No newline at end of file