70518 Remove unused host_app_editable_cocoapods template files (a: existing-apps, cla: yes, tool)

70617 Add liblzma as an explicit dependancy on Linux (cla: yes, team, tool, waiting for tree to go green)

70647 Allow any iOS app to be added to an existing host app (a: existing-apps, cla: yes, platform-ios, team, tool, waiting for tree to go green)

70649 Exclude ARM from macOS builds architectures (cla: yes, platform-mac, t: xcode, tool, waiting for tree to go green)

70712 Roll package:dds to 1.5.1 and add isCompleted guards around completers in base/dds.dart (cla: yes, team, tool, waiting for tree to go green)