Strip lines when log-tailing (#973)

Summary:

For some reason, certain jobs have logs that end in \n\n, making unreadable whitespace

This diff explicitly strips lines before prefixing them, and then manually adds back exactly one "\n"

Created from CodeHub with https://fburl.com/edit-in-codehub

Reviewed By: haonans, tonykao8080

Differential Revision: D66191123

Author: Julie Ganeshan

torchx/util/log_tee_helpers.py

@@ -102,7 +102,7 @@ def _print_log_lines_for_role_replica(
                 color_begin = ""
                 color_end = ""
             prefix = f"{color_begin}{which_role}/{which_replica}{color_end} "
-            print(_prefix_line(prefix, line), file=dst, end="", flush=True)
+            print(_prefix_line(prefix, line.strip()), file=dst, end="\n", flush=True)
     except Exception as e:
         exceptions.put(e)
         raise