Switch to `MoreLikeThis` class in the search controller

[zackkrida]

I noticed that instead of specifying the query type as a string in the earch controller, we can instead import the MoreLikeThis query type directly for the related image query.

openverse-api/api/catalog/api/controllers/search_controller.py

Line 424 in a6c959b

"more_like_this",

[Akshat977]

Hi @zackkrida ,
This issue seems to be a good initiation of my journey towards contribution to FOSS projects.
Can you please assign this to me?

[zackkrida]

Sure @Akshat977!

[ritesh-pandey]

@Akshat977 Are you still working on this?