rust: Add export_include_dirs property to rust_ffi

The cc property include_dirs is neverallowed in certain paths since it
has been deprecated. The property in rust_ffi modules with the same name  functionally works the same way as the CC property export_include_dirs.

To reduce confusion, and avoid triggering the neverallow rule, deprecate
include_dirs and create an export_include_dirs property which does the
same thing. This brings rust module properties into better alignment
with cc module property as well, reducing confusion.

Bug: 330736943
Test: New Soong test
Change-Id: Ib2020a22e6747ac690c46dbff84e38744f93ed15
diff --git a/rust/vendor_snapshot_test.go b/rust/vendor_snapshot_test.go
index 7ebe66b..a6ed0e5 100644
--- a/rust/vendor_snapshot_test.go
+++ b/rust/vendor_snapshot_test.go
@@ -32,7 +32,7 @@
 		crate_name: "ffivendor_available",
 		srcs: ["lib.rs"],
 		vendor_available: true,
-		include_dirs: ["rust_headers/"],
+		export_include_dirs: ["rust_headers/"],
 	}
 
 	rust_ffi {
@@ -40,7 +40,7 @@
 		crate_name: "ffivendor",
 		srcs: ["lib.rs"],
 		vendor: true,
-		include_dirs: ["rust_headers/"],
+		export_include_dirs: ["rust_headers/"],
 	}
 
 	rust_library {