Security Policy Project modal refreshes dropdown when bottom is reached instead of showing loading icon and adding more options

Summary

• Security Policy Project modal refreshes dropdown when bottom is reached instead of showing loading icon and adding more options

The following discussion from !145045 (merged) should be addressed:

• @bauerdominic started a discussion: (+3 comments)

  As the query doesn't support pagination, do we need those parameters?

Implementation

• frontend update spp_selector to implement infinite scroll without the dropdown refreshing the whole list (like the storybook example)