FIR: Resolve error expression in initializer of FirField

^KT-54775 Fixed

compiler/fir/analysis-tests/testData/resolve/kt54775.fir.txt

@@ -0,0 +1,15 @@
+FILE: kt54775.kt
+    public final fun <T> bar(): R|T| {
+        ^bar (Null(null) as R|T|)
+    }
+    public final class X : <ERROR TYPE REF: Symbol not found for B> {
+        public constructor(): R|X| {
+            super<R|kotlin/Any|>()
+        }
+
+        private final field $$delegate_0: <ERROR TYPE REF: Symbol not found for B> = ERROR_EXPR(Should have delegate)
+
+        public final val prop: <ERROR TYPE REF: Should have initializer> = ERROR_EXPR(Should have initializer)
+            public get(): <ERROR TYPE REF: Should have initializer>
+
+    }

compiler/fir/analysis-tests/testData/resolve/kt54775.kt

@@ -0,0 +1,8 @@
+fun <T> bar(): T {
+    return null <!UNCHECKED_CAST!>as T<!>
+}
+
+class X() : <!UNRESOLVED_REFERENCE, UNRESOLVED_REFERENCE!>B<!> by <!ASSIGNMENT_IN_EXPRESSION_CONTEXT!><!VARIABLE_EXPECTED!>get()<!> = bar()<!> {
+    val prop = <!ASSIGNMENT_IN_EXPRESSION_CONTEXT!><!VARIABLE_EXPECTED!>bar()<!> = 2<!>
+}
+