T16617 model source

[niden]

Hello!

• Type: bug fix
• Link to issue: [BUG]: if model has field source ,it cannot be assigned by assign #16617

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

Fixed Phalcon\Mvc\Model::assign() and Phalcon\Mvc\Model::writeAttribute() silently dropping values for columns whose name maps to a reserved internal setter (source, schema, dirtyState, connectionService, readConnectionService, writeConnectionService, eventsManager, transaction, snapshotData, oldSnapshotData); Phalcon\Mvc\Model::possibleSetter() returned true for these reserved names while skipping both the setter call and the property assignment, so the value never landed on the model. It now returns false for reserved setters, letting the caller fall through to direct property assignment while still preventing the reserved internal setter from being hijacked by the column

Thanks