Fix release builds by adding proguard rule for DataStore

Bug: 228863401

Change-Id: I6cd43b0ed7844f7622e362fb77e5213064a629f3

core-datastore/build.gradle.kts

@@ -28,6 +28,12 @@ plugins {
     id("nowinandroid.spotless")
 }
 
+android {
+    defaultConfig {
+        consumerProguardFiles("consumer-proguard-rules.pro")
+    }
+}
+
 // Setup protobuf configuration, generating lite Java and Kotlin classes
 protobuf {
     protoc {

core-datastore/consumer-proguard-rules.pro

@@ -0,0 +1,4 @@
+# Keep DataStore fields
+-keepclassmembers class * extends com.google.protobuf.GeneratedMessageLite* {
+   <fields>;
+}