add beforeLeave event hook on before setPage on router

[DJafari]

i think sometimes need run async function before change page, for example i want hide my modal before going to next page

[DJafari]

this can do by only three change!
if possible add this

public visit(
    href: string | URL,
    {
      method = 'get',
      data = {},
      replace = false,
      preserveScroll = false,
      preserveState = false,
      only = [],
      headers = {},
      errorBag = '',
      forceFormData = false,
      onCancelToken = () => {},
      onBefore = () => {},
      onStart = () => {},
      onProgress = () => {},
+     onBeforeLeave = () => {},
      onFinish = () => {},
      onCancel = () => {},
      onSuccess = () => {},
      onError = () => {},
      queryStringArrayFormat = 'brackets',
    }: VisitOptions = {},
  ): void {

-.then((response) => {
+.then(async (response) => {
  if (!this.isInertiaResponse(response)) {
    return Promise.reject({ response })
  }

  const pageResponse: Page = response.data
  if (only.length && pageResponse.component === this.page.component) {
    pageResponse.props = { ...this.page.props, ...pageResponse.props }
  }
  preserveScroll = this.resolvePreserveOption(preserveScroll, pageResponse) as boolean
  preserveState = this.resolvePreserveOption(preserveState, pageResponse)
  if (preserveState && window.history.state?.rememberedState && pageResponse.component === this.page.component) {
    pageResponse.rememberedState = window.history.state.rememberedState
  }
  const requestUrl = url
  const responseUrl = hrefToUrl(pageResponse.url)
  if (requestUrl.hash && !responseUrl.hash && urlWithoutHash(requestUrl).href === responseUrl.href) {
    responseUrl.hash = requestUrl.hash
    pageResponse.url = responseUrl.href
  }
+ await onBeforeLeave(this.page)
  return this.setPage(pageResponse, { visitId, replace, preserveScroll, preserveState })
})