ci(lts): email only non-zero score patches

This changes the email content to only email those patches which have
non-zero score. This is in order to reduce the noise from patches with
score of zero.

Signed-off-by: Okash Khawaja <okash@google.com>
Change-Id: I443899dfa003c399e5751cc5e1b01e8b08a9ae3e
diff --git a/lts/lts-triage.py b/lts/lts-triage.py
index 244a2e1..eb73456 100644
--- a/lts/lts-triage.py
+++ b/lts/lts-triage.py
@@ -136,10 +136,10 @@
         debug_print("# score after process_ps:", score)
 
         ln = f"{cmt.summary}:    {score}"
-        file_str += ln + "\n"
         print(ln)
 
         if score > 0:
+            file_str += ln + "\n"
             at_least_one_match = True
 
         cnt = cnt - 1