aconfig: change flag values to enabled/disabled enum

Change the underlying type of a flag's value from bool to an explicit
enum (Disabled, Enabled): this will hopefully reduce future confusion on
how flags are intended to be used.

Bug: 279485059
Test: atest aconfig.test
Change-Id: I9535f9b23baf93ad5916ca06fb7d21277b4573eb
diff --git a/tools/aconfig/src/protos.rs b/tools/aconfig/src/protos.rs
index e9a1ab5..604eca4 100644
--- a/tools/aconfig/src/protos.rs
+++ b/tools/aconfig/src/protos.rs
@@ -45,6 +45,9 @@
 #[cfg(not(feature = "cargo"))]
 pub use aconfig_protos::aconfig::Permission as ProtoPermission;
 
+#[cfg(not(feature = "cargo"))]
+pub use aconfig_protos::aconfig::Flag_state as ProtoFlagState;
+
 // ---- When building with cargo ----
 #[cfg(feature = "cargo")]
 include!(concat!(env!("OUT_DIR"), "/aconfig_proto/mod.rs"));
@@ -67,6 +70,9 @@
 #[cfg(feature = "cargo")]
 pub use aconfig::Permission as ProtoPermission;
 
+#[cfg(feature = "cargo")]
+pub use aconfig::Flag_state as ProtoFlagState;
+
 // ---- Common for both the Android tool-chain and cargo ----
 use anyhow::Result;