Fix InvalidCastException when initializing the properties of an undeclared class inside a lambda function

[andrei-ungureanu-uipath]

Fixes #72456.

Building the following snippet in a VB project breaks the compilation:

Imports System
Imports System.Linq.Expressions
Module Program
    Public Function CreateExpression() As Expression(Of Func(Of Object))
        Return Function() (New UndeclaredClass() With {.Name = "testName"})
    End Function
End Module

There is a difference between VisualBasic and CSharp when getting diagnostics for the snippet above. The latter checks for the initializer type while the former forces a DirectCast which throws an InvalidCastException. This PR checks the type before forcing the cast similar to the CSharp approach.

Expected result

Error BC30002: Type 'UndeclaredClass' is not defined.

Actual result

Compilation breaks with the following trace:

System.InvalidCastException
  HResult=0x80004002
  Message=Unable to cast object of type 'Microsoft.CodeAnalysis.VisualBasic.BoundLiteral' to type 'Microsoft.CodeAnalysis.VisualBasic.BoundAssignmentOperator'.

This exception was originally thrown at this call stack:
Microsoft.CodeAnalysis.VisualBasic.dll!Microsoft.CodeAnalysis.VisualBasic.DiagnosticsPass.VisitObjectInitializerExpression(Microsoft.CodeAnalysis.VisualBasic.BoundObjectInitializerExpression node) Line 126	Basic
Microsoft.CodeAnalysis.VisualBasic.dll!Microsoft.CodeAnalysis.VisualBasic.BoundObjectInitializerExpression.Accept(Microsoft.CodeAnalysis.VisualBasic.BoundTreeVisitor visitor) Line 3792	Basic
Microsoft.CodeAnalysis.VisualBasic.dll!Microsoft.CodeAnalysis.VisualBasic.BoundTreeWalkerWithStackGuard.VisitExpressionWithoutStackGuard(Microsoft.CodeAnalysis.VisualBasic.BoundExpression node) Line 61	Basic
Microsoft.CodeAnalysis.VisualBasic.dll!Microsoft.CodeAnalysis.VisualBasic.BoundTreeVisitor.VisitExpressionWithStackGuard(Integer recursionDepth, Microsoft.CodeAnalysis.VisualBasic.BoundExpression node) Line 186	Basic
Microsoft.CodeAnalysis.VisualBasic.dll!Microsoft.CodeAnalysis.VisualBasic.BoundTreeWalkerWithStackGuard.Visit(Microsoft.CodeAnalysis.VisualBasic.BoundNode node) Line 50	Basic
Microsoft.CodeAnalysis.VisualBasic.dll!Microsoft.CodeAnalysis.VisualBasic.DiagnosticsPass.Visit(Microsoft.CodeAnalysis.VisualBasic.BoundNode node) Line 208	Basic
...

[andrei-ungureanu-uipath]

@dotnet-policy-service agree

[AlekseyTs]

Done with review pass (commit 1)

[AlekseyTs]

LGTM (commit 2)

[AlekseyTs]

@dotnet/roslyn-compiler For the second review

[AlekseyTs]

@andrei-ungureanu-uipath Thank you for the contribution.