Merge "Don't show staged value if flag is RO" into main am: 112c4886c7

Original change: https://android-review.googlesource.com/c/platform/build/+/3268192

Change-Id: Ib6ba91a642f719d603907adbe8c323582badec49
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

tools/aconfig/aflags/src/main.rs

@@ -116,9 +116,10 @@ impl Flag {
     }
 
     fn display_staged_value(&self) -> String {
-        match self.staged_value {
-            Some(v) => format!("(->{})", v),
-            None => "-".to_string(),
+        match (&self.permission, self.staged_value) {
+            (FlagPermission::ReadOnly, _) => "-".to_string(),
+            (FlagPermission::ReadWrite, None) => "-".to_string(),
+            (FlagPermission::ReadWrite, Some(v)) => format!("(->{})", v),
         }
     }
 }