[GH] Move ndkVersion setting into a shared .gradle file

Playground builds were overriding the installed ndk version due to agp default and lack of ndkVersion declaration in settings.gradle.

Test: ./gradlew datastore:datastore-core:tasks
Change-Id: Id6d8d9cff46ba3aa3e929e4a7df4912672a12f3a

This is an imported pull request from https://github.com/androidx/androidx/pull/693.

Resolves #693
Github-Pr-Head-Sha: 39d14d48951d2df7e9d158e601bd9230921953a5
GitOrigin-RevId: 2d2f60d3a059f28f96ba873b6d34150af33022c8
Change-Id: Ie9fc432b8b5d47309fe406829b6093323782df20
diff --git a/playground-projects/fragment-playground/settings.gradle b/playground-projects/fragment-playground/settings.gradle
index bf5e622..e1587c0d 100644
--- a/playground-projects/fragment-playground/settings.gradle
+++ b/playground-projects/fragment-playground/settings.gradle
@@ -20,8 +20,11 @@
 }
 plugins {
     id "playground"
+    id "com.android.settings" version "8.7.0-alpha02"
 }
 
+apply from: "../../buildSrc/ndk.gradle"
+
 rootProject.name = "fragment-playground"
 
 playground {