fix: update logviz docs (#12815)

Running `cargo test -p near-chunks test_multi -- --show-output` doesn't
produce any output because the test doesn't exist anymore. Let's update
the docs to use a test that exists on current `master`.

cspell.json

@@ -128,6 +128,7 @@
         "locustfile",
         "locustfiles",
         "Logunov",
+        "logviz",
         "manytx",
         "Mbps",
         "memtable",
@@ -329,4 +330,4 @@
     ],
     "ignoreWords": [],
     "import": []
-}
+}

tools/debug-ui/README.md

@@ -60,7 +60,7 @@ more precisely, using TestLoop from core/async/src/test_loop.rs), the test can b
 
 1. First run the test from the Rust side and save the output, e.g.
    ```
-   cargo test -p near-chunks test_multi -- --show-output > ~/log.txt
+   cargo test -p integration-tests slow_test_client_with_multi_test_loop -- --show-output > ~/log.txt
    ```
 2. Go to the UI at `/logviz`, such as http://localhost:3000/logviz
 3. Drag the log.txt file into the UI.