fix(react): use custom animation when going back after a replace (#28674)

Issue number: resolves #28673

---------

<!-- Please do not submit updates to dependencies unless it fixes an
issue. -->

<!-- Please try to limit your pull request to one type (bugfix, feature,
etc). Submit multiple pull requests if needed. -->

## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->

When reviewing https://github.com/ionic-team/ionic-framework/pull/28671
I noticed a bug where the custom animation was not used when going back
after a replace.

`handleNavigate` will override whatever is in `incomingRouteParams`.
Since we were passing `routeAnimation` (which is `undefined`), it was
overriding the animation we set in `handleNavigateBack`.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- `routeAnimation` is no longer overridden

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this introduces a breaking change, please describe the impact
and migration path for existing applications below. -->


## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

Dev build: `7.6.1-dev.11702048520.13c82dad`