Remove innerHTML check and rely on types instead. Also remove null as…

… a valid type.

src/__tests__/screen.js

@@ -46,12 +46,6 @@ test('logs messsage when element is not a valid HTML', () => {
   expect(console.log.mock.calls[0][0]).toMatchInlineSnapshot(
     `"The element you're providing isn't a valid DOM element."`,
   )
-  console.log.mockClear()
-  screen.logTestingPlaygroundURL({})
-  expect(console.log).toHaveBeenCalledTimes(1)
-  expect(console.log.mock.calls[0][0]).toMatchInlineSnapshot(
-    `"The element you're providing isn't a valid DOM element."`,
-  )
 })
 
 test('logs Playground URL that are passed as element', () => {

src/playground-helper.ts

@@ -10,8 +10,9 @@ function encode(value: string) {
   return compressToEncodedURIComponent(unindent(value))
 }
 
-function getPlaygroundUrl(element: Element | null) {
-  if (!element || !('innerHTML' in element)) {
+function getPlaygroundUrl(element: Element) {
+  // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+  if (!element) {
     throw new Error(`The element you're providing isn't a valid DOM element.`)
   }