[macOS] Remove DS_Store WindowBounds bytes object

Summary:
Backport Core PR14416

Fixes an issue with the dmg building on osx 10.14

Test Plan:

make deploy

test opening image

Reviewers: #bitcoin_abc, jasonbcox

Reviewed By: #bitcoin_abc, jasonbcox

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D2053