MASP shielded sync client phase 1

.changelog/unreleased/improvements/3405-phase-1-shielded-sync-refactor.md

@@ -0,0 +1,7 @@
+ - Implements phase 1 of Issue [\#3385](https://github.com/anoma/namada/issues/3385)
+   - When fetching notes, connections and related failures should not halt shielded sync. Instead, the process
+     should be restarted
+   - If fetching is interrupted, the data fetched should be persisted locally so that progress isn't lost.
+   -  A trait for fetching behavior should be added to provide modularity
+
+      ([\#3498](https://github.com/anoma/namada/pull/3498))

crates/apps_lib/src/cli/client.rs

@@ -12,7 +12,7 @@ use crate::cli::cmds::*;
 use crate::client::{rpc, tx, utils};
 
 impl CliApi {
-    pub async fn handle_client_command<C, IO: Io>(
+    pub async fn handle_client_command<C, IO: Io + Send + Sync>(
         client: Option<C>,
         cmd: cli::NamadaClient,
         io: IO,