FIR: take lower priority into account during references EagerResolve

#KT-48158 Fixed

compiler/testData/diagnostics/tests/callableReference/unitAdaptationForReferenceCompatibility.fir.kt

@@ -20,6 +20,6 @@ public interface Executor {
 fun f(): String = "test"
 
 class A {
-    fun schedule1(e: Executor): Future<String> = <!RETURN_TYPE_MISMATCH, TYPE_MISMATCH!>e.submit(::f)<!>
+    fun schedule1(e: Executor): Future<String> = e.submit(::f)
     fun schedule2(e: Executor): Future<String> = <!RETURN_TYPE_MISMATCH, TYPE_MISMATCH!>e.submit { f() }<!>
 }