[Obs AI Assistant] Remove the copy button if there is no content to c…

…opy (elastic#199064)

Closes elastic#196986

## Summary

### Problem
The copy button for a visualization does nothing, as there's no content
to copy. When clicked on this button, a message is shown saying "Copied
Message", but nothing is copied.

### Solution
Remove the copy button, when there's no content to copy.

### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

x-pack/packages/kbn-ai-assistant/src/chat/chat_item.tsx

@@ -99,7 +99,7 @@ export function ChatItem({
   const [editing, setEditing] = useState<boolean>(false);
   const [expanded, setExpanded] = useState<boolean>(Boolean(element));
 
-  const actions = [canCopy, collapsed, canCopy].filter(Boolean);
+  const actions = [canCopy, collapsed].filter(Boolean);
 
   const noBodyMessageClassName = css`
     ${moreCompactHeaderClassName}
@@ -182,7 +182,7 @@ export function ChatItem({
         />
       }
       className={
-        actions.length === 0 && !content
+        actions.length === 0 && !content && !element
           ? noPanelMessageClassName
           : collapsed
           ? noBodyMessageClassName

x-pack/packages/kbn-ai-assistant/src/utils/get_timeline_items_from_conversation.test.tsx

@@ -247,7 +247,7 @@ describe('getTimelineItemsFromConversation', () => {
 
       expect(pick(items[3], 'actions', 'display')).toEqual({
         actions: {
-          canCopy: true,
+          canCopy: false,
           canEdit: false,
           canGiveFeedback: false,
           canRegenerate: false,

x-pack/packages/kbn-ai-assistant/src/utils/get_timeline_items_from_conversation.tsx

@@ -130,7 +130,6 @@ export function getTimelineItemsfromConversation({
 
       switch (role) {
         case MessageRole.User:
-          actions.canCopy = true;
           actions.canGiveFeedback = false;
           actions.canRegenerate = false;
 
@@ -210,11 +209,16 @@ export function getTimelineItemsfromConversation({
             display.collapsed = false;
           }
 
+          if (!content) {
+            actions.canCopy = false;
+          } else {
+            actions.canCopy = true;
+          }
+
           break;
 
         case MessageRole.Assistant:
           actions.canRegenerate = hasConnector;
-          actions.canCopy = true;
           actions.canGiveFeedback = true;
           display.hide = false;
 
@@ -250,6 +254,13 @@ export function getTimelineItemsfromConversation({
             display.collapsed = false;
             actions.canEdit = false;
           }
+
+          if (!content) {
+            actions.canCopy = false;
+          } else {
+            actions.canCopy = true;
+          }
+
           break;
       }