Fix SSR receiving value update cause other inputs to lose focus

[amoshydra]

Change

This PR will check if there is a range selected in quill and call it only when necessary.

Expected behaviour

Updating value of the editor should not blur other input fields

Current behaviour

When the SSR version of vue-quill-editor receive an updated value it will attempt to restore the selection within the text field.

if (newData) {
  if (newData != oldData) {
    const range = quill.getSelection()
    quill.root.innerHTML = newData
    setTimeout(() => {
      quill.setSelection(range)
    })
  }

https://github.com/surmon-china/vue-quill-editor/blob/02c1741/src/ssr.js#L134-L141

However, quill.setSelection(range) is called even when vue-quill-editor is not focused. This usually cause the variable range to be null. Thus, setSelection(null) will cause quill to clear all selection instead (edit: Including all inputs fields within the page) See: https://github.com/quilljs/quill/blob/16d4130a75d7bc2bfb7315694e69d1e08f764641/core/selection.js#L339

Example: https://codepen.io/amoshydra/pen/ZjYbRa

• Initially the example input field has focus and has text selected
• Afterquill.setSelection(null) is called the input field lose selection and lose focus