tui: drop stale legacy message snapshot test

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__deltas_then_same_final_message_are_rendered_snapshot.snap

@@ -1,5 +0,0 @@
----
-source: tui/src/chatwidget/tests.rs
-expression: combined
----
-

codex-rs/tui/src/chatwidget/tests.rs

@@ -8486,68 +8486,6 @@ async fn final_reasoning_then_message_without_deltas_are_rendered() {
     assert_snapshot!(combined);
 }
 
-#[tokio::test]
-async fn deltas_then_same_final_message_are_rendered_snapshot() {
-    let (mut chat, mut rx, _op_rx) = make_chatwidget_manual(None).await;
-
-    // Stream some reasoning deltas first.
-    chat.handle_codex_event(Event {
-        id: "s1".into(),
-        msg: EventMsg::AgentReasoningDelta(AgentReasoningDeltaEvent {
-            delta: "I will ".into(),
-        }),
-    });
-    chat.handle_codex_event(Event {
-        id: "s1".into(),
-        msg: EventMsg::AgentReasoningDelta(AgentReasoningDeltaEvent {
-            delta: "first analyze the ".into(),
-        }),
-    });
-    chat.handle_codex_event(Event {
-        id: "s1".into(),
-        msg: EventMsg::AgentReasoningDelta(AgentReasoningDeltaEvent {
-            delta: "request.".into(),
-        }),
-    });
-    chat.handle_codex_event(Event {
-        id: "s1".into(),
-        msg: EventMsg::AgentReasoning(AgentReasoningEvent {
-            text: "request.".into(),
-        }),
-    });
-
-    // Then stream answer deltas, followed by the exact same final message.
-    chat.handle_codex_event(Event {
-        id: "s1".into(),
-        msg: EventMsg::AgentMessageDelta(AgentMessageDeltaEvent {
-            delta: "Here is the ".into(),
-        }),
-    });
-    chat.handle_codex_event(Event {
-        id: "s1".into(),
-        msg: EventMsg::AgentMessageDelta(AgentMessageDeltaEvent {
-            delta: "result.".into(),
-        }),
-    });
-
-    chat.handle_codex_event(Event {
-        id: "s1".into(),
-        msg: EventMsg::AgentMessage(AgentMessageEvent {
-            message: "Here is the result.".into(),
-            phase: None,
-        }),
-    });
-
-    // Snapshot the combined visible content to ensure we render as expected
-    // when deltas are followed by the identical final message.
-    let cells = drain_insert_history(&mut rx);
-    let combined = cells
-        .iter()
-        .map(|lines| lines_to_single_string(lines))
-        .collect::<String>();
-    assert_snapshot!(combined);
-}
-
 // Combined visual snapshot using vt100 for history + direct buffer overlay for UI.
 // This renders the final visual as seen in a terminal: history above, then a blank line,
 // then the exec block, another blank line, the status line, a blank line, and the composer.