[FIR] Remove FirLambdaArgumentExpression

It's not really necessary if the information about if the lambda was a
trailing lambda can be directly saved in FirAnonymousFunctionExpression.

Removing the FIR node uncovered a couple of bugs
(UNINITIALIZED_ENUM_ENTRY, ERROR_IN_CONTRACT_DESCRIPTION) that were
caused by assuming that a lambda is always a trailing lambda.

#KT-66124

analysis/analysis-api/testData/components/callResolver/resolveCall/labeledLambda.txt

@@ -0,0 +1,28 @@
+KtSuccessCallInfo:
+  call = KtSimpleFunctionCall:
+    isImplicitInvoke = false
+    partiallyAppliedSymbol = KtPartiallyAppliedSymbol:
+      dispatchReceiver = null
+      extensionReceiver = null
+      signature = KtFunctionLikeSignature:
+        receiverType = null
+        returnType = kotlin.Unit
+        symbol = /foo(l1: kotlin.Function1<kotlin.Int, kotlin.Unit>): kotlin.Unit
+        valueParameters = [
+          KtVariableLikeSignature:
+            name = l1
+            receiverType = null
+            returnType = kotlin.Function1<kotlin.Int, kotlin.Unit>
+            symbol = l1: kotlin.Function1<kotlin.Int, kotlin.Unit>
+            callableIdIfNonLocal = null
+        ]
+        callableIdIfNonLocal = /foo
+    typeArgumentsMapping = {}
+    argumentMapping = {
+      label@ {} -> (KtVariableLikeSignature:
+        name = l1
+        receiverType = null
+        returnType = kotlin.Function1<kotlin.Int, kotlin.Unit>
+        symbol = l1: kotlin.Function1<kotlin.Int, kotlin.Unit>
+        callableIdIfNonLocal = null)
+    }