Node Handler check, is not handling mjs file extension bug

[Engerim]

Description

The node handler check is not handling the file extension for esm modules (mjs) correctly, so you always see as an error in aws lambdas, and this is misleading
Startup check failed: missing handler file newrelic-lambda-wrapper.handler (NEW_RELIC_LAMBDA_HANDLER=src/handler.sqsHandler)

Steps to Reproduce

• use nr lambda layers
• have a mjs file as a handler
• NEW_RELIC_USE_ESM env is set to true
• the check will print this error Startup check failed: missing handler file newrelic-lambda-wrapper.handler (NEW_RELIC_LAMBDA_HANDLER=src/handler.sqsHandler)

Expected Behavior

• the check should not print the error

Additional context

• the tests are passing as this part is not tested in the code

A Patch for the test setup like it happens when you use the nr lambda layers and the setup
this patch let the test fails as it really runs through the code

Index: checks/handler_check_test.go
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/checks/handler_check_test.go b/checks/handler_check_test.go
--- a/checks/handler_check_test.go	(revision 039e826cac93eb276be1e614485ae38721cdd4f3)
+++ b/checks/handler_check_test.go	(date 1709044901494)
@@ -110,8 +110,9 @@
 	os.MkdirAll(filepath.Join(handlerPath, "path", "to"), os.ModePerm)
 	os.Create(filepath.Join(handlerPath, "path", "to", "app.mjs"))
 
-	reg.Handler = testHandler
-	conf.NRHandler = config.EmptyNRWrapper
+	reg.Handler = "newrelic-lambda-wrapper.handler"
+	os.Setenv("NEW_RELIC_USE_ESM", "true")
+	conf = config.Configuration{TestingOverride: false, NRHandler: testHandler}
 	err = handlerCheck(ctx, &conf, &reg, r)
 	assert.Nil(t, err)
 }

[workato-integration]

https://new-relic.atlassian.net/browse/NR-371643