Fix subprocess.run for progressive mode

[kostyaplis]

Fixes #2314

Several issues I've noticed with recently introduced subprocess.run for git commands in progressive mode:

1. git rev-parse HEAD^1 returns a newline, so have to be stripped, otherwise error
2. git worktree add -f worktree_dir uses shell=True. It expects a string so it fails with a list of arguments as reported in issue Progressive mode is broken as of 6.5.0 #2314 )
3. git checkout revision uses shell=True. Same as above
4. git worktree add -f worktree_dir uses check=True. It fails when the directory already exists. So each subsequent ansible-lint run will fail