Fix setting File as value in store (T1327666)

[GoodDayForSurf]

No description provided.

[Copilot]

Pull request overview

Fixes T1327666 where assigning a File (or Blob) as a value through deepExtendArraySafe/newAssign would corrupt the value by attempting to deep-clone it via Object.create(Object.getPrototypeOf(item)). The fix short-circuits deepExtendArraySafe when changes is a Blob-like instance, returning it by reference.

Changes:

• Add isBlobLike helper that safely checks for Blob (guarding against environments where Blob is undefined).
• Short-circuit deepExtendArraySafe to return the value when changes is a Blob/File.
• Add a QUnit test verifying Blob/File values are preserved by reference both as nested properties and as the top-level changes argument.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
packages/devextreme/js/__internal/core/utils/m_object.ts	Adds isBlobLike guard and early return in deepExtendArraySafe to preserve Blob/File references.
packages/devextreme/testing/tests/DevExpress.core/utils.object.tests.js	New QUnit test covering Blob/File assignment via deepExtendArraySafe with newAssign.