Standardize URL parameter handling in urlBuilders

[coderabbitai]

A potential inconsistency was identified in the handling of the chatbot parameter within the urlBuilders methods.

Details:

• In threadUrl, chatbot uses toSlug(chatbot)
• In userChatbotUrl, chatbot uses chatbot.toLowerCase()

This discrepancy could lead to URL mismatches. It is recommended to standardize the approach using toSlug for consistency.

Refer to PR #316 and the comment: #316 (comment)

Requested by @AndlerRL.