#41898 fix!: livechat autocomplete endpoints accept unsafe selector parameter

Proposed changes (including videos or screenshots)

This PR remove the conditions parameter from the selector input in the livechat autocomplete endpoints (livechat/department.autocomplete and livechat/visitors.autocomplete), following the deprecation introduced in #41766. The parameter is now fully removed as part of the 9.0.0 major release.

Issue(s)

CORE-2609

Steps to test or reproduce

Further comments

Summary by CodeRabbit

• Bug Fixes
  • Improved department and visitor autocomplete results when searching by term and applying exclusions.
  • Removed unsupported query conditions from autocomplete requests, preventing unintended filtering.
  • Standardized autocomplete request handling for more consistent and reliable results.
  • Removed unsafe selector parameters from livechat autocomplete endpoints, reducing the risk of unexpected search behavior.