Remove unnecessary files in RN-Tester (#37152)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/37152

Those files are unncessary and can be removed from RNTester.
* Proguard file is empty
* Signing config is unnecessary and we can use the debug one also for release.

Changelog:
[Internal] [Changed] - Remove unnecessary files in RN-Tester

Reviewed By: hoxyq

Differential Revision: D45399388

fbshipit-source-id: fd1c6cccaef668e688a699e31045bdc8103ea98e

packages/rn-tester/android/app/build.gradle

@@ -123,14 +123,6 @@ android {
         testBuildType System.getProperty('testBuildType', 'debug')  // This will later be used to control the test apk build type
         testInstrumentationRunner 'androidx.test.runner.AndroidJUnitRunner'
     }
-    signingConfigs {
-        release {
-            storeFile file(MYAPP_RELEASE_STORE_FILE)
-            storePassword MYAPP_RELEASE_STORE_PASSWORD
-            keyAlias MYAPP_RELEASE_KEY_ALIAS
-            keyPassword MYAPP_RELEASE_KEY_PASSWORD
-        }
-    }
     externalNativeBuild {
         cmake {
             version cmakeVersion
@@ -145,15 +137,10 @@ android {
         }
     }
     buildTypes {
-        debug {
-            debuggable true
-            signingConfig signingConfigs.release
-        }
         release {
-            debuggable false
             minifyEnabled enableProguardInReleaseBuilds
-            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
-            signingConfig signingConfigs.release
+            proguardFiles getDefaultProguardFile('proguard-android.txt')
+            signingConfig signingConfigs.debug
         }
     }
     sourceSets.main {

packages/rn-tester/android/app/gradle.properties

@@ -1,11 +1,6 @@
 org.gradle.parallel=true
 # This is causing issue with dependencies task: https://github.com/gradle/gradle/issues/9645#issuecomment-530746758
 # org.gradle.configureondemand=true
-MYAPP_RELEASE_STORE_FILE=my-release-key.keystore
-MYAPP_RELEASE_KEY_ALIAS=androiddebugkey
-MYAPP_RELEASE_STORE_PASSWORD=android
-MYAPP_RELEASE_KEY_PASSWORD=android
-
 android.useAndroidX=true
 android.enableJetifier=true
 

packages/rn-tester/android/app/proguard-rules.pro

@@ -1,15 +0,0 @@
-# Copyright (c) Meta Platforms, Inc. and affiliates.
-#
-# This source code is licensed under the MIT license found in the
-# LICENSE file in the root directory of this source tree.
-
-# Add project specific ProGuard rules here.
-# By default, the flags in this file are appended to flags specified
-# in /usr/local/Cellar/android-sdk/24.3.3/tools/proguard/proguard-android.txt
-# You can edit the include path and order by changing the proguardFiles
-# directive in build.gradle.
-#
-# For more details, see
-#   http://developer.android.com/guide/developing/tools/proguard.html
-
-# Add any project specific keep options here: