Have one and only one \n character at the end of the system-probe.yaml (#49885)

Recent change corrected the missing tailing \n in the system-probe.yaml and another removed it by mistake.

This missing \n shouldn't have execution impact since it doesn't prevent the yaml parsing.

However, this caused the agent_linux_install_script’s unit test to fail, as the script checks for the configuration by ensuring it is POSIX-compliant which expect a tailing \n

Co-authored-by: stanislas.plowiecki <stanislas.plowiecki@datadoghq.com>

Author: Stanislas167

pkg/config/render_config/render_config.go

@@ -113,20 +113,17 @@ func mkContext(buildType string, osName string) context {
 }
 
 func render(destFile string, tplFile string, component string, osName string) {
-	f, err := os.Create(destFile)
-	if err != nil {
-		panic(err)
-	}
-
 	tplFilename := filepath.Base(tplFile)
 
 	t := template.Must(template.New(tplFilename).ParseFiles(tplFile))
-	err = t.Execute(f, mkContext(component, osName))
-	if err != nil {
+	var buf bytes.Buffer
+	if err := t.Execute(&buf, mkContext(component, osName)); err != nil {
 		panic(err)
 	}
 
-	if err := f.Close(); err != nil {
+	rendered := append(bytes.TrimRight(buf.Bytes(), "\n\r \t"), '\n')
+
+	if err := os.WriteFile(destFile, rendered, 0644); err != nil {
 		panic(err)
 	}
 }

tasks/schema/template.py

@@ -392,7 +392,7 @@ def generate_template(schema_file, dest, build_type, os_target):
 
     final_render = [line.strip() for line in config_template.strip().split("\n")]
     with open(dest, "w") as f:
-        f.write("\n".join(final_render))
+        f.write("\n".join(final_render) + "\n")
 
 
 @task(