#64063 Remove legacy certs and update the associated Grunt commands

[johnbillion]

Trac ticket: Core-64063.

One potential concern is whether anyone is relying on the cacert.pem file to exist. For example:

wp_remote_get(
  'https://example.com',
  [
    'sslcertificates' => ABSPATH . 'wp-includes/certificates/cacert.pem',
  ]
);

[github-actions]

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[Copilot]

Pull request overview

This pull request removes legacy 1024-bit SSL certificates from WordPress and simplifies the certificate bundle build process by eliminating the concatenation step that previously combined legacy certificates with the current certificate bundle.

Changes:

• Removed the legacy-1024bit.pem file containing expired 1024-bit Verisign certificates
• Removed legacy certificate headers and content from ca-bundle.crt
• Updated Grunt build tasks to copy certificates directly instead of concatenating multiple files

Reviewed changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated no comments.

File	Description
src/wp-includes/certificates/legacy-1024bit.pem	Deleted file containing outdated 1024-bit certificates for backward compatibility
src/wp-includes/certificates/ca-bundle.crt	Removed prepended legacy certificates, now contains only current Mozilla CA bundle
Gruntfile.js	Updated certificate build workflow to copy directly from composer package instead of concatenating, removed obsolete file exclusions and concat task

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[github-actions]

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[johnbillion]

@desrosj I added the removed files to $_old_files. How's this looking?