FFs can now be toggled in release builds too (#3101)

- Removed `StaticFeatureFlagProvider`.
- Always provide `PreferencesFeatureFlagProvider`.
- For the default values of feature flags, use a lambda with a `BuildMeta` parameter so we can customize the return value based on its data.

libraries/featureflag/api/build.gradle.kts

@@ -23,5 +23,7 @@ android {
 }
 
 dependencies {
+    implementation(projects.appconfig)
+    implementation(projects.libraries.core)
     implementation(libs.coroutines.core)
 }