Update MCR link to points to mcr.microsoft.com instead of the core ACR marketing page

[Ricky-G]

The link for "mcr.microsoft.com" was incorrectly referencing the ACR marketing page instead of the actual MCR

[learn-build-service-prod[bot]]

Learn Build status updates of commit a40df56:

:warning: Validation status: warnings

File	Status	Preview URL	Details
virtualization/windowscontainers/manage-containers/container-base-images.md	:warning:Warning		Details

virtualization/windowscontainers/manage-containers/container-base-images.md

• Line 102, Column 194: [Warning: file-not-found - See documentation] Invalid file link: 'mcr.microsoft.com'.

For more details, please refer to the build report.

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