Make the commandsHandler and the mention methods public to allow customization of the mention command handler

[sheep-q]

🔗 Issue Links

N/A

🎯 Goal

Allow customization of the mention command handler

📝 Summary

Make the commandsHandler and the mention methods public

🛠 Implementation

In the MessageComposerViewModel.swift, make the following public:

• property commandsHandler
• method checkForMentionedUsers
• method clearRemovedMentions
• method clearInputData
• method checkChannelCooldown

🎨 Showcase

Add relevant screenshots and/or videos/gifs to easily see what this PR changes, if applicable.

Before	After
img	img

🧪 Manual Testing Notes

Explain how this change can be tested manually, if applicable.

☑️ Contributor Checklist

• I have signed the Stream CLA (required)
• This change should be manually QAed
• Changelog is updated with client-facing changes
• Changelog is updated with new localization keys
• New code is covered by unit tests
• Documentation has been updated in the docs-content repo