[Parser] Fix parsing of unfinished dot access in string template

Problem appeared in cases like this: "{someVar.}"

#KT-34440 Fixed

compiler/testData/diagnostics/tests/kt34440.kt

@@ -0,0 +1,9 @@
+// ISSUE: KT-34440
+
+class BufferUtil {
+    fun isDirect(cond: Boolean): Boolean =
+        when (<!UNUSED_EXPRESSION!>cond<!>) {
+            else -> throw Exception("${<!UNRESOLVED_REFERENCE!>buf<!>.<!SYNTAX!><!>}")
+        }
+    private class BufferInfo(private val type: Class<*>)
+}