Prioritize RedfishRoute-owning chassis over sensor collection append mode

When `sensor_collection_append_sub_module` is enabled, `sensor::RegisterRoutesAppendMode` previously omitted the `TLBMC_ROUTE` collection route (`/redfish/v1/Chassis/<str>/Sensors/`). This prevented chassis with `"OwnsSensorsCollection": true` from being claimed in `owned_urls` and incorrectly routed their sensor collection queries to gBMCWeb.

This change registers the collection route alongside the append handler, allowing `SmartRouter` to route `RedfishRoute`-owning chassis directly to tlBMC while preserving append mode for non-owning chassis.

PiperOrigin-RevId: 928782020
Change-Id: Icceb1b288b669c537cc76057cbc931f3f15cb4cd