Fix Intel Mac build action

[simonhamp]

What does this PR do?

Fixes the Intel Mac build GitHub Action as it was missing the PHP runtime, Composer and other parts necessary to run the build process from SPC source.

Checklist before merging

If your PR involves the changes mentioned below and completed the action, please tick the corresponding option. If a modification is not involved, please skip it directly.

• [ ] If it's a extension or dependency update, make sure adding related extensions in src/global/test-extensions.php.
• [ ] If you changed the behavior of static-php-cli, add docs in static-php/static-php-cli-docs .
• [ ] If you updated config/xxxx.json content, run bin/spc dev:sort-config xxx.