Allow editor when not in tty

I was told there are legitimate use cases I was not aware of.

toot/cli/post.py

@@ -130,9 +130,6 @@ def post(
     json: bool
 ):
     """Post a new status"""
-    if editor and not sys.stdin.isatty():
-        raise click.ClickException("Cannot run editor if not in tty.")
-
     if len(media) > 4:
         raise click.ClickException("Cannot attach more than 4 files.")