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.

features/onboarding/impl/src/test/kotlin/io/element/android/features/onboarding/impl/OnBoardingPresenterTest.kt

@@ -35,13 +35,18 @@ class OnBoardingPresenterTest {
 
     @Test
     fun `present - initial state`() = runTest {
+        val buildMeta = aBuildMeta(
+            applicationName = "A",
+            productionApplicationName = "B",
+            desktopApplicationName = "C",
+        )
+        val featureFlagService = FakeFeatureFlagService(
+            initialState = mapOf(FeatureFlags.QrCodeLogin.key to true),
+            buildMeta = buildMeta,
+        )
         val presenter = OnBoardingPresenter(
-            buildMeta = aBuildMeta(
-                applicationName = "A",
-                productionApplicationName = "B",
-                desktopApplicationName = "C",
-            ),
-            featureFlagService = FakeFeatureFlagService(initialState = mapOf(FeatureFlags.QrCodeLogin.name to true)),
+            buildMeta = buildMeta,
+            featureFlagService = featureFlagService,
         )
         moleculeFlow(RecompositionMode.Immediate) {
             presenter.present()