Fix /collections-search q, filter

[jonhealy1]

Related Issue(s):

• None

Description:

• Fixed filter parameter handling for GET /collections-search endpoint. Filter parameters (filter and filter-lang) are now properly passed through and processed.
• Fixed q parameter in GET /collections-search endpoint to be converted to a list format, matching the behavior of the /collections endpoint for consistency.

PR Checklist:

• Code is formatted and linted (run pre-commit run --all-files)
• Tests pass (run make test)
• Documentation has been updated to reflect changes, if applicable
• Changes are added to the changelog