Refactor LimitOffsetPagingSourceTest to use paging-testing artifact

Add paging-testing to COMPOSE build subset because room-paging belongs in COMPOSE subset and all its dependencies are required to be as well

Test: ./gradlew room:room-paging:cC
Bug: n/a
Change-Id: I4b2a0d4be59bdba619dfe08b941aa27e85214ca2

diff --git a/settings.gradle b/settings.gradle
index 3e517c5..bf5bfdc 100644
--- a/settings.gradle
+++ b/settings.gradle

@@ -767,7 +767,7 @@
 includeProject(":paging:paging-rxjava2-ktx", [BuildType.MAIN])
 includeProject(":paging:paging-rxjava3", [BuildType.MAIN])
 includeProject(":paging:paging-samples", "paging/samples", [BuildType.MAIN, BuildType.COMPOSE])
-includeProject(":paging:paging-testing", [BuildType.MAIN])
+includeProject(":paging:paging-testing", [BuildType.MAIN, BuildType.COMPOSE])
 includeProject(":palette:palette", [BuildType.MAIN])
 includeProject(":palette:palette-ktx", [BuildType.MAIN])
 includeProject(":percentlayout:percentlayout", [BuildType.MAIN])