Add separate language filters for agent and customer messages

The platform currently allows users to filter chats by language. It also supports applying certain filters separately to the call center agent and the customer.

The language filter should be extended so users can independently filter chats by:

• the language used by the agent;

• the language used by the customer.

This is required for conversations where the participants may use different languages.

Current Behavior

The language filter is applied to the chat as a whole.

It is not possible to specify whether the selected language was used by the agent or by the customer.

Expected Behavior

Add two separate language filters:

• Agent Language

• Customer Language

Each filter should return chats where the selected language was detected for the corresponding conversation participant.

Users should be able to:

• apply only the Agent Language filter;

• apply only the Customer Language filter;

• apply both filters simultaneously;

• combine these filters with other available filters.

Acceptance Criteria

1. The filter panel contains separate Agent Language and Customer Language filters.

2. When an Agent Language is selected, the results include only chats where that language was detected for the agent.

3. When a Customer Language is selected, the results include only chats where that language was detected for the customer.

4. When both filters are applied, the results include only chats matching both selected conditions.

5. The same language can be selected for both participants.

6. Different languages can be selected for the agent and the customer.

7. The new filters can be combined with existing chat filters.

8. Clearing one language filter does not reset the other filter.

9. Existing general language filtering behavior remains unchanged unless it is intentionally replaced by the new participant-specific filters.

Origin - https://enderturing.freshdesk.com/a/tickets/423