This PR fixes the dropping of both the `path` and `search` fields from the platform location in the URL when using Flutter Web and brings it in par with similar technologies (e.g. React Router).
It allows developers to keep the original path and/or search parameters in the URL, which are perfectly valid even while fragment routing is present.

**Example use case:**
Call a Flutter Web app with initial config parameters in the URL: 
`http://my-flutter.app/?skipIntro=true`

**Example:**
Before initial routing:
`http://localhost:45389/?foo=bar`
After routing:
`http://localhost:45389/#/menu`
After routing (with fix):
`http://localhost:45389/?foo=bar#menu`

Fixes #116415