[Impeller] Eliminate some shared_ptr copying from EntityPass::Render (flutter/engine#49855)

Every drop counts right?

engine/src/flutter/impeller/entity/entity_pass.cc

@@ -333,8 +333,8 @@ bool EntityPass::Render(ContentContext& renderer,
                   Rect::MakeSize(root_render_target.GetRenderTargetSize()),
                   {.readonly = true});
 
-  IterateAllEntities([lazy_glyph_atlas =
-                          renderer.GetLazyGlyphAtlas()](const Entity& entity) {
+  const auto& lazy_glyph_atlas = renderer.GetLazyGlyphAtlas();
+  IterateAllEntities([&lazy_glyph_atlas](const Entity& entity) {
     if (const auto& contents = entity.GetContents()) {
       contents->PopulateGlyphAtlas(lazy_glyph_atlas, entity.DeriveTextScale());
     }