fix(TopicChannelDetails): avatar and subtitle parsing

[absidue]

Description

This pull request fixes the title and subtitle properties on the TopicChannelDetails being identical and the avatar array being empty.

I haven't come across a case where data.thumbnail actually existed but I've left it in there just in case there is an edge case that uses it.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have checked my code and corrected any misspellings