Remove unused perception branches (pointfreeco#3376)

Author: stephencelis

Sources/ComposableArchitecture/Internal/Exports.swift

@@ -4,16 +4,9 @@
 @_exported import ConcurrencyExtras
 @_exported import CustomDump
 @_exported import Dependencies
+@_exported import DependenciesMacros
 @_exported import IdentifiedCollections
+@_exported import Observation
+@_exported import Perception
 @_exported import SwiftUINavigation
 @_exported import UIKitNavigation
-
-#if canImport(DependenciesMacros)
-  @_exported import DependenciesMacros
-#endif
-#if canImport(Observation)
-  @_exported import Observation
-#endif
-#if canImport(Perception)
-  @_exported import Perception
-#endif