An incorrect selection is uploaded if you resize or move it before saving a shot

[SoftVision-CiprianMuresan]

[Affected versions]:

• Nightly 53.0a1
• Page Shot 3.0-dev

[Affected Platforms]:

• All Windows

[Prerequisites]:

• Page Shot add-on was previously installed on a new profile from https://pageshot.dev.mozaws.net/homepage/install-test-local.html.

[Steps to reproduce]:

1. Open the browser with the profile from prerequisites and navigate to a web page.
2. Click on "Page Shot" icon from the browser toolbar.
3. Drag the mouse on the screen to make a selection.
4. Move the selection to a different part of the screen.
5. Click the "Save" button.

[Expected result]:

• The image is uploaded and displayed successfully.

[Actual result]:

• The image is uploaded, but the initial selection is saved instead of the custom one.

[Notes]:

• This issue is also reproducible on the Page Shot version from Test Pilot.