Warmup molecule only once.

tests/testutils/src/main/kotlin/io/element/android/tests/testutils/WarmUpRule.kt

@@ -33,8 +33,16 @@ import kotlin.time.Duration.Companion.seconds
  * inside runTest which has a short default timeout.
  */
 class WarmUpRule : TestRule {
-    override fun apply(base: Statement, description: Description): Statement = object: Statement() {
+    companion object {
-        override fun evaluate() {
+        init {
+            warmUpMolecule()
+        }
+    }
+
+    override fun apply(base: Statement, description: Description): Statement = base
+}
+
+private fun warmUpMolecule() {
     runTest(timeout = 60.seconds) {
         moleculeFlow(RecompositionMode.Immediate) {
             // Do nothing
@@ -42,7 +50,4 @@ class WarmUpRule: TestRule {
             awaitItem() // Await a Unit composition
         }
     }
-            base.evaluate()
-        }
-    }
 }