Added git remote prune origin and git fetch --prune for sdk and each submodule to ensure there is no tracking of remote stale branches.
Now fails if any submodule first commit is orphan, instead of checking just the last submodule (submodules shells are communicating exit code through 'exit_code_file'
Checked that there is no false positive nor false negative by creating 2 dummy branches in msaaudio and ms2, committed 2 times, then merged dummyBrach2 in dummyBranch with squash and branch delete, without updating submodules in sdk
