Add support for `double` typed carrier config

Bug: 230375219
Change-Id: I550ad9a5f8fcd0a3574975b5133a107b39920f79
Test: none - proto definition change
diff --git a/proto/carrier_settings.proto b/proto/carrier_settings.proto
index da75c60..5a18c24 100644
--- a/proto/carrier_settings.proto
+++ b/proto/carrier_settings.proto
@@ -183,6 +183,7 @@
       TextArray text_array = 6;
       IntArray int_array = 7;
       CarrierConfig bundle = 8;
+      double double_value = 9;
     }
   }