Ignore filter clause when value does not appear in any document

Description

Currently, the "override rules" functionality allows us to define only simple string values for overriding configurations. It would be highly beneficial to enhance this functionality by supporting additional regex rules.

Dynamic Filters Question

curl "http://localhost:8108/collections/companies/overrides/brand-filter" -X PUT \
-H "Content-Type: application/json" \
-H "X-TYPESENSE-API-KEY: ${TYPESENSE_API_KEY}" -d '{
  "rule": {
    "query": "{brand} phone",
    "match": "contains"
  },
  "filter_by": "brand:={brand}",
  "remove_matched_tokens": true
}'

What if I want to ignore the filter_by rule if the brand does not exist in my list of brands? Is there a way to conditionally apply the filter based on the presence of brand in the list?

Start with the override-rules endpoint example for /collections/companies/overrides/brand-filter and its dynamic filter_by value, brand:={brand}. Trace how override rules and filters are applied, then define completion as conditionally ignoring the filter when the requested brand is absent while preserving the existing behavior when it is present.