Fix bug in RPC server implmentation of dashboard overview data

Apparently you are not allowed to spawn an executor to call other endpoints.
So we just factor out the logic of the `get_confirmations` endpoint to an
internal function such that it can be reused.

src/rpc_server.rs

@@ -138,6 +138,27 @@ pub struct NeptuneRPCServer {
     pub rpc_server_to_main_tx: tokio::sync::mpsc::Sender<RPCServerToMain>,
 }
 
+impl NeptuneRPCServer {
+    fn confirmations_internal(&self) -> Option<BlockHeight> {
+        match executor::block_on(self.state.get_latest_balance_height()) {
+            Some(latest_balance_height) => {
+                let tip_block_header =
+                    executor::block_on(self.state.chain.light_state.get_latest_block_header());
+
+                assert!(tip_block_header.height >= latest_balance_height);
+
+                // subtract latest balance height from chain tip.
+                // note: BlockHeight is u64 internally and BlockHeight::sub() returns i128.
+                //       The subtraction and cast is safe given we passed the above assert.
+                let confirmations: BlockHeight =
+                    ((tip_block_header.height - latest_balance_height) as u64).into();
+                Some(confirmations)
+            }
+            None => None,
+        }
+    }
+}
+
 impl RPC for NeptuneRPCServer {
     async fn get_network(self, _: context::Context) -> Network {
         self.state.cli.network
@@ -159,22 +180,7 @@ impl RPC for NeptuneRPCServer {
     }
 
     async fn get_confirmations(self, _: context::Context) -> Option<BlockHeight> {
-        match executor::block_on(self.state.get_latest_balance_height()) {
-            Some(latest_balance_height) => {
-                let tip_block_header =
-                    executor::block_on(self.state.chain.light_state.get_latest_block_header());
-
-                assert!(tip_block_header.height >= latest_balance_height);
-
-                // subtract latest balance height from chain tip.
-                // note: BlockHeight is u64 internally and BlockHeight::sub() returns i128.
-                //       The subtraction and cast is safe given we passed the above assert.
-                let confirmations: BlockHeight =
-                    ((tip_block_header.height - latest_balance_height) as u64).into();
-                Some(confirmations)
-            }
-            None => None,
-        }
+        self.confirmations_internal()
     }
 
     async fn head(self, _: context::Context) -> Digest {
@@ -323,7 +329,7 @@ impl RPC for NeptuneRPCServer {
 
     async fn get_dashboard_overview_data(
         self,
-        context: tarpc::context::Context,
+        _context: tarpc::context::Context,
     ) -> DashBoardOverviewDataFromClient {
         let tip_header = executor::block_on(self.state.chain.light_state.get_latest_block_header());
         let wallet_status = executor::block_on(self.state.get_wallet_status_for_tip());
@@ -342,7 +348,7 @@ impl RPC for NeptuneRPCServer {
             Err(_) => None,
         };
 
-        let confirmations = executor::block_on(self.get_confirmations(context));
+        let confirmations = self.confirmations_internal();
 
         DashBoardOverviewDataFromClient {
             tip_header,