Add Android imports for some new tests in #3308 that require it (#3334)

My Android CI [just broke because it couldn't find these newly used C
symbols in the NIO
tests](https://github.com/finagolfin/swift-android-sdk/actions/runs/16768316992/job/47477878652#step:19:242),
this patch [fixed it
again](https://github.com/finagolfin/swift-android-sdk/actions/runs/16787226279/job/47540691932).
Unsure why this only affects Android, likely the module leaks postulated
before.

Author: finagolfin

Tests/NIOEmbeddedTests/AsyncTestingChannelTests.swift

@@ -18,6 +18,10 @@ import XCTest
 
 @testable import NIOEmbedded
 
+#if canImport(Android)
+import Android
+#endif
+
 @available(macOS 10.15, iOS 13, tvOS 13, watchOS 6, *)
 class AsyncTestingChannelTests: XCTestCase {
     func testSingleHandlerInit() async throws {

Tests/NIOEmbeddedTests/EmbeddedChannelTest.swift

@@ -19,6 +19,10 @@ import XCTest
 
 @testable import NIOEmbedded
 
+#if canImport(Android)
+import Android
+#endif
+
 final class ChannelLifecycleHandler: ChannelInboundHandler, Sendable {
     public typealias InboundIn = Any