[CX-6832] Populate is_read_only when creating AdminIdentity from a Convex Access Token (#27468)

GitOrigin-RevId: 42bd6b3550fa7b05086c2ac6a3e06f9b0fae7fda

Author: pashabitz

crates/keybroker/src/broker.rs

@@ -561,12 +561,13 @@ impl AdminIdentity {
         instance_name: String,
         principal: AdminIdentityPrincipal,
         access_token: String,
+        is_read_only: bool,
     ) -> Self {
         Self {
             instance_name,
             principal,
             key: access_token,
-            is_read_only: false,
+            is_read_only,
         }
     }