[macOS]Update Xcode to 26.0 RC1 to macOS15 images

[sureshe456]

Description

1. Update Xcode to 26.0 RC1 to macOS15 images.

Related issue:

#12991

Check list

• Related issue / work item is attached
• Tests are written (if applicable)
• Documentation is updated (if applicable)
• Changes are tested and related VM images are successfully generated

[Copilot]

Pull Request Overview

Updates the Xcode version from 26.0.0-Beta.7 to 26.0 Release Candidate on macOS 15 images for both x64 and arm64 architectures.

• Updates Xcode link references from beta 7 to Release Candidate
• Updates filename references to use Release Candidate naming
• Updates SHA256 checksums for the new RC1 build

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[joogps]

Why is the iOS 26.0 SDK not included with this image? It sounds like it should according to the readme. CC/ @sureshe456

[erik-bershel]

Hey @joogps!

SDK will be there but we avoiding installing simulator runtimes for that beta. To many issues with that version. We'll be deployed with the release.

[theblixguy]

@erik-bershel Since this is an RC and likely the final Xcode 26 build, will the simulator runtime be added later?

[erik-bershel]

Hey @theblixguy

@erik-bershel Since this is an RC and likely the final Xcode 26 build, will the simulator runtime be added later?

Nope. Read above.