fix(dashboards): metric widget overflow (#64644)

Author: obostjancic

static/app/views/dashboards/dashboard.tsx

@@ -630,6 +630,4 @@ const WidgetWidthWrapper = styled('div')`
   left: 16px !important;
   right: 16px !important;
   width: auto !important;
-  /* minimal working z-index */
-  z-index: 6;
 `;

static/app/views/dashboards/widgetCard/metricWidgetCard/inlineEditor.tsx

@@ -346,6 +346,8 @@ const InlineEditorWrapper = styled('div')`
   padding: ${space(1)};
   gap: ${space(1)};
   width: 100%;
+  /* minimal z-index that allows dropdowns to expand over other dashboard elements */
+  z-index: 6;
 `;
 
 const QueryDefinitionWrapper = styled('div')`