Remove signingConfig from release build type

Removed signing configuration for release build type.

Author: bmc08gt

apps/flipcash/app/build.gradle.kts

@@ -65,7 +65,6 @@ android {
     buildTypes {
         getByName("release") {
             resValue("string", "applicationId", appNamespace)
-            signingConfig = signingConfigs.getByName("contributors")
             isMinifyEnabled = true
             isShrinkResources = true
             proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")