The management of `browserUrlTree` currently has several problems with
correctly tracking the actual state of the browser.
This change makes the Router eagerly update the `browserUrlTree` when
handling navigations triggered by browser events (i.e., not 'imperative'). This
is because with those types of navigations, the browser URL bar is
_already_ updated. If we do not update the internal tracking of the
`browserUrlTree`, we will be out of sync with the real URL if the
navigation is rejected.
It would be best if we could remove `browserUrlTree` completely, but doing that
would require a lot more investigation and is blocked by #27059 because
the SpyLocation used in tests does not emulate real browser behavior.
fixes#43101
PR Close#43102
286b2807de