Make ImageView zoom scale dynamic with window size

[roryabraham]

Details

Following up on #6535, cc @railway17

Fixed Issues

$ none

Tests / QA Steps

1. Prepare a very long image.
2. Send the image to someone.
3. Click the image thumbnail in the chatbox.
4. Verify modal opens to display the image.
5. Verify image is center aligned.
6. Check the cursor while hovering around the image.
7. Check the zoom in and zoom out functionality.
8. Resize the window and make sure the image zoom region adjusts accordingly
9. Prepare a very wide image and send it to another.
10. Repeat steps 2-8 with the wide image.

Tested On

• Web
• Mobile Web
• Desktop
• iOS
• Android

Screenshots

Web

Mobile Web

Desktop

iOS

Android

[roryabraham]

Don't remember the context here, going to just close this.