fix: add line break to gradle.properties for template testing (#57107)

Summary:
This fixes the failing CI jobs on main for `template` testing. The job fails as they echo `react.internal.mavenLocalRepo=...` to the `gradle.properties` of template test project. As a result of which the `gradle.properties` look like below:

```properties
android.builtInKotlin=false
android.newDsl=falsereact.internal.mavenLocalRepo=...
```

To fix it we add a line break in the `echo` command.

## Changelog:

<!-- Help reviewers and the release process by writing your own changelog entry.

Pick one each for the category and type tags:

[ANDROID|GENERAL|IOS|INTERNAL] [BREAKING|ADDED|CHANGED|DEPRECATED|REMOVED|FIXED|SECURITY] - Message

For more details, see:
https://reactnative.dev/contributing/changelogs-in-pull-requests
-->

[INTERNAL] [FIXED] - add line break to gradle.properties for template testing

Pull Request resolved: #57107

Test Plan:
- CI Passing
- Verified Locally

Reviewed By: cortinico

Differential Revision: D107880136

Pulled By: cipolleschi

fbshipit-source-id: 81cf2fe53c1c2285f79db538aa5aa3cb745f796d

Author: hurali97

.github/workflows/e2e-android-templateapp.yml

@@ -66,7 +66,7 @@ jobs:
 
           echo "Feed maven local to gradle.properties"
           cd /tmp/RNTestProject
-          echo "react.internal.mavenLocalRepo=$MAVEN_LOCAL" >> android/gradle.properties
+          echo "\nreact.internal.mavenLocalRepo=$MAVEN_LOCAL" >> android/gradle.properties
 
           # Build
           cd android

scripts/release-testing/test-release-local.js

@@ -292,7 +292,7 @@ async function testRNTestProject(
 
   // need to do this here so that Android will be properly setup either way
   exec(
-    `echo "react.internal.mavenLocalRepo=${mavenLocalPath}" >> android/gradle.properties`,
+    `echo "\nreact.internal.mavenLocalRepo=${mavenLocalPath}" >> android/gradle.properties`,
   );
 
   // Only build the simulator architecture. CI is however generating only that one.