Fix: ensure Save Draft and Publish buttons are disabled during media upload

[Ashok-A15]

Problem

The "Save Draft" and "Publish" buttons are not consistently disabled during media uploads, which can lead to flaky behavior in editor interactions and failing E2E tests.

Cause

The disabled state logic relied on a complex conditional that did not reliably reflect the post saving lock state (isPostSavingLocked), especially during media uploads.

Solution

Simplified the disabled state logic for both Save Draft and Publish buttons to ensure they are consistently disabled when:

• the post is saving
• the post is not saveable
• publishing is not allowed
• the post saving lock is active (e.g., during media uploads)

Changes

• Simplified isButtonDisabled condition
• Simplified isToggleDisabled condition
• Ensured consistent behavior during upload and save states

Testing

• Ran E2E tests (upload-save-lock.spec.js)
• Verified that:
  • Save Draft button is disabled during single image upload
  • Save Draft button is disabled during multi-image upload
  • Publish button is disabled during upload
  • Buttons are re-enabled after upload completes

Result

Fixes flaky behavior and ensures UI correctly reflects upload/save lock state.

[github-actions]

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Co-authored-by: Ashok-A15 <ashokearappa@git.wordpress.org>
Co-authored-by: adamsilverstein <adamsilverstein@git.wordpress.org>

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[github-actions]

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[adamsilverstein]

Hi @Ashok-A15 thanks for the bug report. I noticed some tests are failing, can you address that.

Also can you add some testing steps and information about your setup.

[github-actions]

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• Labels found: [Package] Editor, First-time Contributor.

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[adamsilverstein]

ps. this should have been fixed in #76973