fix: remove superfluous spaces when normalizing class (#3083)

Co-authored-by: Jacek Karczmarczyk <jkarczm@gmail.com>

packages/shared/__tests__/normalizeProp.spec.ts

@@ -0,0 +1,17 @@
+import { normalizeClass } from '../src'
+
+describe('normalizeClass', () => {
+  test('handles string correctly', () => {
+    expect(normalizeClass('foo')).toEqual('foo')
+  })
+
+  test('handles array correctly', () => {
+    expect(normalizeClass(['foo', undefined, true, false, 'bar'])).toEqual('foo bar')
+  })
+
+  test('handles object correctly', () => {
+    expect(normalizeClass({ foo: true, bar: false, baz: true })).toEqual(
+      'foo baz'
+    )
+  })
+})