Fix css embed in JSX when using (only) a spread attribute (#15896)

tests/format/jsx/embed/__snapshots__/jsfmt.spec.js.snap

@@ -0,0 +1,15 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`css-embed.js format 1`] = `
+====================================options=====================================
+parsers: ["flow", "babel"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+<style {...spread}>{\`.{}\`}</style>;
+
+=====================================output=====================================
+<style {...spread}>{\`.{}\`}</style>;
+
+================================================================================
+`;

tests/format/jsx/embed/css-embed.js

@@ -0,0 +1 @@
+<style {...spread}>{`.{}`}</style>;

tests/format/jsx/embed/jsfmt.spec.js

@@ -0,0 +1 @@
+run_spec(import.meta, ["flow", "babel"]);