[CDF-25251] Search configuration resource loader (#1864)

# Description

Stacked on #1907 
This PR introduces the SearchConfigLoader, a new resource loader that
enables the toolkit to read and handle SearchConfig resource
configurations. This loader addresses a current limitation in the search
config API where configurations are not properly handled on a per-view
basis. To resolve this, the toolkit now merges all configurations for a
single view into a unified object. This object is then updated whenever
a new configuration view property is modified, ensuring that changes are
correctly applied and that a new configuration is not created
unnecessarily during a POST request without an id field.
## Changelog

- [x] Patch
- [ ] Skip

## cdf

### Added

- [alpha] Added a search configuration resource loader
SearchConfigLoader.

## templates

No changes.
