feat(insights): remove spans tab from spans summary (#87890)

Deprecate `spans` tab in the transaction summary page
<img width="574" alt="image"
src="https://github.com/user-attachments/assets/c424d071-ddab-4751-958c-41d6fc3d7db2"
/>

I did check, and I could not find anything that links to this page, but
in the odd chance something does I marked the tab as `hidden` so the
link still works and we can track page usage to see if it's being
accessed

Follow up PR will be created to cleanup remaining code, and remove
`hidden`

Author: DominikB2014

static/app/views/performance/transactionSummary/header.tsx

@@ -206,7 +206,9 @@ function TransactionHeader({
             <TabList.Item key={Tab.TRANSACTION_SUMMARY}>{t('Overview')}</TabList.Item>
             <TabList.Item key={Tab.EVENTS}>{t('Sampled Events')}</TabList.Item>
             <TabList.Item key={Tab.TAGS}>{t('Tags')}</TabList.Item>
-            <TabList.Item key={Tab.SPANS}>{t('Spans')}</TabList.Item>
+            <TabList.Item key={Tab.SPANS} hidden>
+              {t('Spans')}
+            </TabList.Item>
             <TabList.Item
               key={Tab.WEB_VITALS}
               textValue={t('Web Vitals')}