[CI][Github] Disable premerge workflow on main

Trying to switch over to the normal execution mode and running into issues.
Turning this off on main for now while I investigate given my time
availability is a bit sparse today.

Author: boomanaiden154

.github/workflows/premerge.yaml

@@ -7,9 +7,6 @@ on:
   pull_request:
     paths:
       - .github/workflows/premerge.yaml
-  push:
-    branches:
-      - 'main'
 
 jobs:
   premerge-checks-linux: