fix dioxus core event tests

packages/core/Cargo.toml

@@ -36,6 +36,7 @@ serde = { version = "1", features = ["derive"], optional = true }
 [dev-dependencies]
 tokio = { workspace = true, features = ["full"] }
 dioxus = { workspace = true }
+dioxus-html = { workspace = true, features = ["serialize"] }
 pretty_assertions = "1.3.0"
 rand = "0.8.5"
 dioxus-ssr = { workspace = true }