• I've read the guidelines for contributing and seen the walkthrough
• I've posted a comment on an issue with a detailed description of how I am planning to contribute and got approval from a member of the team
• The code builds and tests pass locally (also verified by our automated build checks)
• Commit messages follow this format:
  Summary of the changes

1. Core Expression Enhancements
   ProjectionBindingExpression: Introduced the UpdateType(Type type) method. Since Expressions are immutable, this allows creating a new instance with a refined type. This is crucial for changing the "expected type" of a projection without wrapping it in a UnaryExpression (Convert node).

2. Shaper Logic Optimization
   ProjectionBindingExpressionVisitor.MatchTypes: Updated the logic to check if an expression is a ProjectionBindingExpression. Instead of returning Expression.Convert(expression, targetType), it now calls projectionBindingExpression.UpdateType(targetType). This results in a much flatter and cleaner shaper expression tree.

3. Provider Clean-up (Relational & Cosmos)
   RelationalProjectionBindingExpressionVisitor: Removed several calls to .MakeNullable(). By passing the raw expression.Type, we avoid unnecessary MakeGenericType calls, which is a significant win for NativeAOT and trimming. The MatchTypes logic now handles necessary conversions more intelligently.

CosmosProjectionBindingExpressionVisitor: Applied the same clean-up to the Cosmos provider, bringing it up to parity with the relational implementation.

Fixes ##36572

• Tests for the changes have been added (for bug fixes / features)
• Code follows the same patterns and style as existing code in this repo