[build] Make line check run only on main branch (#1617)

PR commit change check should run only against main branch, otherwise hotfix releases might fail.

Author: majisourav99

.github/pull_request_template.md

@@ -18,6 +18,8 @@ Describe
 - What issues or limitations exist in the current code
 - Why this change is necessary 
 -->
+
+
 ## Solution
 <!--
 Describe

.github/workflows/limit-pr-files-changed.yml

@@ -2,6 +2,8 @@ name: Enforce Max Lines Changed Per File
 
 on:
   pull_request:
+    branches:
+      - main
     paths:
       - '**/*.java'   # Monitor changes to Java files
       - '**/*.avsc'   # Monitor changes to Avro schema files