fix(android): UPnP - add kxml2 to test classpath so DeviceDescriptionTest runs

Android's XmlPullParserFactory is a Stub-throwing class in android.jar
on the JVM unit-test classpath; the probe pattern from dc5b8252 was
silently skipping the test suite, which gives false test-coverage
confidence. kxml2 is the same parser implementation Android uses
internally - service-provider lookup picks it up automatically once
on the test classpath.

The probe + Assumptions.assumeTrue skip removed; tests now run
unconditionally.

testImplementation(libs.kxml2) - 2.3.0, MIT-licensed, ~80KB. No
production code change.

android/gradle/libs.versions.toml

@@ -34,6 +34,7 @@ mockk = "1.13.13"
 compose-test = "1.7.5"
 ktlint-gradle = "12.1.1"
 detekt = "2.0.0-alpha.3"
+kxml2 = "2.3.0"
 
 [libraries]
 androidx-core-ktx = { module = "androidx.core:core-ktx", version = "1.13.1" }
@@ -89,6 +90,7 @@ turbine = { module = "app.cash.turbine:turbine", version.ref = "turbine" }
 mockk = { module = "io.mockk:mockk", version.ref = "mockk" }
 compose-ui-test = { module = "androidx.compose.ui:ui-test-junit4" }
 compose-ui-test-manifest = { module = "androidx.compose.ui:ui-test-manifest" }
+kxml2 = { module = "net.sf.kxml:kxml2", version.ref = "kxml2" }
 
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }