FE: add tests for KT-53966 (positive/negative)

compiler/testData/diagnostics/tests/samConversions/samConversionWithCondition.fir.kt

@@ -0,0 +1,14 @@
+fun main() {
+    val flag = true
+    consumeTicker(
+        if (flag) null else <!ARGUMENT_TYPE_MISMATCH!>{ num -> num.<!UNRESOLVED_REFERENCE!>dec<!>() }<!>
+    )
+}
+
+fun consumeTicker(ticker: Ticker?) {
+
+}
+
+fun interface Ticker {
+    fun tick(num: Int)
+}