Resolve merge conflicts.

# Conflicts:
#   briar-android/src/main/java/org/briarproject/briar/android/conversation/AttachmentController.java
#   briar-android/src/main/java/org/briarproject/briar/android/util/UiUtils.java
1 job for 1473-display-multiple-images in 11 minutes and 32 seconds