[Cases] Remove extra gap between template and global fields in case view sidebar

Both were direct children of the xl-gutter flex column, causing an
oversized gap. Wrapping them in a div makes them a single flex item.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: lgestc

x-pack/platform/plugins/shared/cases/public/components/case_view/components/case_view_activity.tsx

@@ -353,10 +353,10 @@ export const CaseViewActivity = ({
             onSubmit={onSubmitCustomField}
           />
           {isTemplatesV2Enabled && (
-            <>
+            <div>
               <TemplateFields caseData={caseData} onUpdateField={onUpdateField} />
               <GlobalCaseFields caseData={caseData} onUpdateField={onUpdateField} />
-            </>
+            </div>
           )}
         </EuiFlexGroup>
       </EuiFlexItem>