fix(ssr): hydration for transition wrapper components with empty slot content (#5995)

fix #5991

packages/compiler-ssr/__tests__/ssrSlotOutlet.spec.ts

@@ -123,7 +123,7 @@ describe('ssr: <slot>', () => {
       "const { ssrRenderSlotInner: _ssrRenderSlotInner } = require(\\"vue/server-renderer\\")
 
       return function ssrRender(_ctx, _push, _parent, _attrs) {
-        _ssrRenderSlotInner(_ctx.$slots, \\"default\\", {}, null, _push, _parent)
+        _ssrRenderSlotInner(_ctx.$slots, \\"default\\", {}, null, _push, _parent, null, true)
       }"
     `)
   })

packages/compiler-ssr/src/transforms/ssrTransformSlotOutlet.ts

@@ -50,6 +50,10 @@ export const ssrTransformSlotOutlet: NodeTransform = (node, context) => {
       parent.children.filter(c => c.type === NodeTypes.ELEMENT).length === 1
     ) {
       method = SSR_RENDER_SLOT_INNER
+      if (!(context.scopeId && context.slotted !== false)) {
+        args.push('null')
+      }
+      args.push('true')
     }
 
     node.ssrCodegenNode = createCallExpression(context.helper(method), args)