[Android] Free Photo Library allows selecting / uploading multiple images, but only shows first one

[mkevins]

Describe the bug
When the user selects "Free photos library" from "single image" blocks (Cover, Image and Media & Text blocks), it allows multiple photos to be selected. This is inconsistent with the other upload options (which only allow a single image to be selected). Additionally, these selected images are all uploaded to the media library upon confirmation, but only the first selected image is displayed in the post.

To Reproduce
Steps to reproduce the behavior:

1. Create a new post
2. Add a cover block
3. Tap "Add image or video"
4. Tap "Choose from Free Photo Library"
5. Type a search term (observe that multiple images can be selected)
6. Select multiple images
7. Tap "Add n" (n is the number of selected images)

Expected behavior
The "Choose from Free Photo Library" option should only allow selection of 1 image.

Note:
In the future, if a feature is designed and implemented that allows for selecting multiple Cover block images, all options should support it consistently, and the images should be displayed in the post when selected.

Smartphone (please complete the following information):

• Device: Pixel 3a
• OS: Android X

Additional context
This is related with a similar bug in iOS, which exhibited different behavior, but also erroneously allowed multiple image selection for this flow.