Cannot download conversation posts in txt mode.

[PixlRainbow]

Describe the bug
When tumblthree downloads a conversation post (on Tumblr) with output set as txt, it does not properly stringify the content of the post; it saves a .NET object class name instead.

To Reproduce
Steps to reproduce the behavior:

1. Add a blog containing old conversation posts.
   I used sleufoot, but this blog will be deleted within the next few hours.
2. Make sure "download conversation posts" is checked in blog details.
3. Add blog to queue and start download.
4. See "conversations.txt" in output folder.

Expected behavior
Conversation posts are converted into HTML unordered lists and saved in conversations.txt

Screenshots
conversations.txt
Example:

Post id: 144817631650
Date: 2016-05-23 18:59:36 GMT
Post url: https://sleufoot.tumblr.com/post/144817631650
Slug: interviewer-so-what-can-you-do-what-are-your
Reblog key: Yt0iU3Dn
Reblog url: 
Reblog name: 
Quote: System.Linq.Enumerable+WhereSelectListIterator`2[TumblThree.Applications.DataModels.TumblrApiJson.Conversation,<>f__AnonymousType0`2[System.String,System.String]]
Body: 
Tags: 

Desktop (please complete the following information):

• TumblThree version: 2.13.0.442 (release)
• OS: Windows 10 Home
• Browser: Firefox
• Version 125.0.3 (64-bit)

Additional context
Download was attempted on very old Tumblr posts from 2016.

[thomas694]

Thanks for reporting a bug. We'll take a look at it.