ensure router.reload data replaces query params

[HamidRezaLS]

PR fixes a bug where router.reload({ data: { ... } }) would incorrectly merge new data with existing query string parameters instead of replacing them.

The Problem:
The old behavior was unpredictable and led to incorrect state. During local testing, I observed the following scenario:

1. A page loads with a prop, for example items: [1, 2].
2. A reload is triggered with data: { items: [3, 4] }. The props correctly update to ['3', '4'].
3. A second reload is then triggered with data: { items: [99] }.
4. The Bug: The props incorrectly become ['99', '4'], because the items[1]=4 parameter from the previous URL was not cleared during the new request.

This change modifies how GET requests handle the data option. The provided data object is now treated as the single source of truth for the new query string, completely overwriting any old parameters.

For developers using Inertia, this makes the router.reload function significantly more predictable and easier to reason about, which helps prevent unexpected behavior in applications.

I've also confirmed that this does not change or break the documented behavior of partial reloads. This fix only affects how the request URL is constructed in url.ts. The client-side prop merging that handles only and except is a separate process and remains untouched.

Fixes: #2285

[pascalbaljet]

Thanks for this! Your change also removes other keys from the query string, so I've opened PR #2417 to handle it more gracefully.