Revert "feat: enable coinbase onramp for supported regions by default"

This reverts commit a77e143.

Author: bmc08gt

apps/flipcash/shared/featureflags/src/main/kotlin/com/flipcash/app/featureflags/FeatureFlag.kt

@@ -102,8 +102,8 @@ sealed interface FeatureFlag {
     @FeatureFlagMarker
     data object CoinbaseOnRamp: FeatureFlag {
         override val key: String = "coinbase_onramp_enabled"
-        override val default: Boolean = true
-        override val launched: Boolean = true
+        override val default: Boolean = false
+        override val launched: Boolean = false
         override val visible: Boolean = true
         override val persistLogOut: Boolean = false
     }