Fix run-name to show only first line of commit message

Use split() to extract only the first line (subject) of the commit message
instead of the entire multi-line message including Co-authored-by and
Signed-off-by lines.

Before: "Fast Build - test: Add tests Co-authored-by: ... Signed-off-by: ..."
After:  "Fast Build - test: Add tests"

Signed-off-by: Mark Pollack <mark.pollack@broadcom.com>

Author: markpollack

.github/workflows/main-push-fast.yml

@@ -1,5 +1,5 @@
 name: Main Push - Fast
-run-name: ${{ github.event.inputs.commit_sha && format('Manual Test - {0}', github.event.inputs.commit_sha) || format('Fast Build - {0}', github.event.head_commit.message) }}
+run-name: ${{ github.event.inputs.commit_sha && format('Manual Test - {0}', github.event.inputs.commit_sha) || format('Fast Build - {0}', split(github.event.head_commit.message, '\n')[0]) }}
 
 on:
   push: