[native] Support Blob service URIs when saving media

Summary: Missing part of D10854. I realized that Blob Service stored media URIs start with blob-service:// and are not recognized by current code. This diff fixes that.

Test Plan:

• Enable blob service uploads in input-state-container
• Send a photo message
• Open the photo modal and click save

Reviewers: atul, ashoat

Reviewed By: ashoat

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D10906