feat(list-item): Add tooltip for expanding and collapsing (#8612)

**Related Issue:** #8613

## Summary

- Adds tooltip for expand/collapse button.

packages/calcite-components/src/components/list-item/assets/list-item/t9n/messages.json

@@ -1,3 +1,5 @@
 {
-  "close": "Close"
+  "close": "Close",
+  "expand": "Expand",
+  "collapse": "Collapse"
 }

packages/calcite-components/src/components/list-item/assets/list-item/t9n/messages_en.json

@@ -1,3 +1,5 @@
 {
-  "close": "Close"
+  "close": "Close",
+  "expand": "Expand",
+  "collapse": "Collapse"
 }

packages/calcite-components/src/components/list-item/list-item.tsx

@@ -471,12 +471,18 @@ export class ListItem
   }
 
   renderOpen(): VNode {
-    const { el, open, openable } = this;
+    const { el, open, openable, messages } = this;
     const dir = getElementDir(el);
     const icon = open ? ICONS.open : dir === "rtl" ? ICONS.closedRTL : ICONS.closedLTR;
+    const tooltip = open ? messages.collapse : messages.expand;
 
     return openable ? (
-      <td class={CSS.openContainer} key="open-container" onClick={this.handleToggleClick}>
+      <td
+        class={CSS.openContainer}
+        key="open-container"
+        onClick={this.handleToggleClick}
+        title={tooltip}
+      >
         <calcite-icon icon={icon} key={icon} scale="s" />
       </td>
     ) : null;