[ME][2.5/7] Simplify transaction adapters

[tomTom1010EEE]

Description

• Remove the Cubemap storage and record-access delegate containers; use existing Core storage types directly.
• Replace Texture2D field-access delegates with direct assignments, keeping animation-binding rollback shared.
• Keep Studio property and texture loading together in one file.

Motivation and Context

Small follow-up to #407 to reduce indirection. One commit based on the merged upstream version; no later maintenance stages or UI changes. Save formats and public APIs are unchanged.

How Has This Been Tested?

All seven targets built successfully. Metadata tests and managed transaction checks passed. The rebased source tree matches the tested tree. No in-game validation of this follow-up yet.

Screenshots (if appropriate):

No visual changes.

Types of changes

• Bug fix
• New feature
• Breaking change
• Refactor / maintenance (no intended behavior change)

[starstormhun]

A bit of moving around code, and some simplifying indeed.