fix(dev-infra): use all non-header content for checking commit body length (#41367)

As discovered in #41316, commit body length checks should consider all of the non-header
content as the commit body rather than the conventional-commit-parser's current method
of considering everything after an issue/PR reference to be the footer.

PR Close #41367

dev-infra/commit-message/validate.ts

@@ -131,8 +131,14 @@ export function validateCommitMessage(
     // Checking commit body //
     //////////////////////////
 
+    // Due to an issue in which conventional-commits-parser considers all parts of a commit after
+    // a `#` reference to be the footer, we check the length of all of the commit content after the
+    // header. In the future, we expect to be able to check only the body once the parser properly
+    // handles this case.
+    const allNonHeaderContent = `${commit.body.trim()}\n${commit.footer.trim()}`;
+
     if (!config.minBodyLengthTypeExcludes?.includes(commit.type) &&
-        commit.body.trim().length < config.minBodyLength) {
+        allNonHeaderContent.length < config.minBodyLength) {
       errors.push(`The commit message body does not meet the minimum length of ${
           config.minBodyLength} characters`);
       return false;