ref(traces): "Add Instrumentation" is a external link (#87415)

<img alt="clipboard.png" width="235"
src="https://i.imgur.com/zqSjrU8.png" />

Before it was

<img alt="clipboard.png" width="224"
src="https://i.imgur.com/hvEG98m.png" />

Author: evanpurkhiser

static/app/views/performance/newTraceDetails/traceActionsMenu.tsx

@@ -1,7 +1,7 @@
 import {openModal} from 'sentry/actionCreators/modal';
 import {Button} from 'sentry/components/core/button';
 import {DropdownMenu} from 'sentry/components/dropdownMenu';
-import {IconEllipsis} from 'sentry/icons';
+import {IconEllipsis, IconOpen} from 'sentry/icons';
 import {t} from 'sentry/locale';
 import type {EventTransaction} from 'sentry/types/event';
 import {trackAnalytics} from 'sentry/utils/analytics';
@@ -103,16 +103,6 @@ function TraceActionsMenu({
             navigate(target);
           },
         },
-        {
-          key: 'custom_instrumentation_button',
-          label: t('Add Instrumentation'),
-          onAction: () => {
-            const docsLink = getCustomInstrumentationLink(traceProject);
-            if (docsLink) {
-              window.location.href = docsLink;
-            }
-          },
-        },
         {
           key: 'shortcuts_button',
           label: t('See Shortcuts'),
@@ -121,6 +111,17 @@ function TraceActionsMenu({
             openModal(props => <TraceShortcutsModal {...props} />);
           },
         },
+        {
+          key: 'external-actions',
+          children: [
+            {
+              key: 'custom_instrumentation_button',
+              label: t('Add Instrumentation'),
+              externalHref: getCustomInstrumentationLink(traceProject),
+              leadingItems: <IconOpen />,
+            },
+          ],
+        },
       ]}
       trigger={triggerProps => (
         <Button