Revert "Add skill approval event/response (#12633)" (#12811)

This reverts commit https://github.com/openai/codex/pull/12633. We no
longer need this PR, because we favor sending normal exec command
approval server request with `additional_permissions` of skill
permissions instead

codex-rs/tui/src/chatwidget.rs

@@ -4455,8 +4455,7 @@ impl ChatWidget {
             | EventMsg::ReasoningContentDelta(_)
             | EventMsg::ReasoningRawContentDelta(_)
             | EventMsg::DynamicToolCallRequest(_)
-            | EventMsg::DynamicToolCallResponse(_)
-            | EventMsg::SkillRequestApproval(_) => {}
+            | EventMsg::DynamicToolCallResponse(_) => {}
             EventMsg::RealtimeConversationStarted(ev) => {
                 if !from_replay {
                     self.on_realtime_conversation_started(ev);