CP-17608 metadata stream

[niden]

Hello!

• Type: bug fix
• Link to issue: [BUG]: MetaData\Stream race between processes caches corrupted metadata #17608

In raising this pull request, I confirm the following:

• I have read and understood the Contributing Guidelines
• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR
• I have updated the relevant CHANGELOG
• I have created a PR for the documentation about this change

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• Phalcon\Mvc\Model\MetaData\Stream letting other processes read a partially written cache file.
• Phalcon\Mvc\Model\MetaData storing a cached value that is not an array as the model meta-data.

Thanks