[BUGFIX] Fix query param redirects during active transitions

[olenderhub]

This fixes redirecting from beforeModel to the same route with updated query params.

When a query-param-only transition was started during an active transition, the router used the query-param-only path. That could lose the updated query params from the URL or crash during direct visits.

This change avoids the query-param-only path while another transition is active, allowing the normal transition path to abort and replace the active transition.

Adds regression coverage for:

• transition entry into the route
• direct visit to the route

Testing

• pnpm test:wip

Fixes #18577
Refs #19609

[NullVoxPopuli]

should #21412 be looked at first? does order matter?

[olenderhub]

@NullVoxPopuli It seems to me that this doesn’t really matter for this PR, so it can be checked independently. It’s a similar issue, but not the same one, in my opinion.