refactor(@angular/ssr): combine redirect URL parameter helpers and use DefaultUrlSerializer #34467

Follow-up to #34321:
- Combines buildPathWithParams and buildQueryWithParams into buildUrlWithParams.
- Reuses DefaultUrlSerializer from @angular/router for query parameter parsing and serialization instead of custom regex/encoding helpers.
- Adds fast-path checks to avoid regex/splitting and URLSearchParams instantiation when redirect targets do not contain placeholders.
- Applies joinUrlParts only to the path portion of redirect targets when prepending baseHref or X-Forwarded-Prefix so trailing slashes in query parameters or fragments are preserved.