Remove rpcQueries import and define local submit function in manage-trust tutorial

Co-authored-by: tamirms <1445829+tamirms@users.noreply.github.com>

Author: Copilot

docs/build/apps/example-application-tutorial/manage-trust.mdx

@@ -66,14 +66,33 @@ The layout of the page is quite similar to our contacts page. It has a table dis
   import { invalidateAll } from "$app/navigation";
 
   // We import some of our `$lib` functions
-  import { submit } from "$lib/stellar/rpcQueries";
   import { createChangeTrustTransaction } from "$lib/stellar/transactions";
   import { fetchAssets } from "$lib/utils/stellarExpert";
+  
+  // We import the Server from @stellar/stellar-sdk/rpc for transaction submission
+  import { Server } from "@stellar/stellar-sdk/rpc";
+  import { error } from "@sveltejs/kit";
 
   // The `open` Svelte context is used to open the confirmation modal
   import { getContext } from "svelte";
   const { open } = getContext("simple-modal");
 
+  // RPC server configuration for transaction submission
+  const rpcUrl = "https://soroban-testnet.stellar.org";
+  const server = new Server(rpcUrl);
+
+  // Local submit function to send transactions using RPC
+  const submit = async (transaction) => {
+    try {
+      await server.sendTransaction(transaction);
+    } catch (err) {
+      throw error(400, {
+        // @ts-ignore
+        message: `${err.response?.title} - ${err.response?.data.extras.result_codes}`,
+      });
+    }
+  };
+
   // Define some component variables that will be used throughout the page
   let addAsset = "";
   let customAssetCode = "";