Enforce Editor Lock for Write, Append, and Upload Operations in DataNode

[PrakharJain1509]

PR Description

Title: Enforce Editor Lock for Write, Append, and Upload Operations in DataNode

Summary

This PR addresses the issue #2017 where a DataNode could be modified by other editors despite being locked by one. It ensures that once a DataNode is locked with an editor_id, no other editor can perform write, append, or upload operations until the lock is released.

Changes Implemented

• Modified the write(), append(), and _upload() methods:
  • Enforced locking mechanism to prevent unauthorized modifications by other editors.
  • Raised DataNodeIsBeingEdited exception when a different editor attempts to modify the locked DataNode.
  • Allowed orchestrator writes without editor_id even during an active lock.
• Updated unit tests in:
  • test_data_node.py to validate the new behavior.
• Ensured 90% code coverage on all modified methods.

Acceptance Criteria Met

• Locking mechanism for write, append, and upload is now enforced as expected.
• Orchestrator writes remain allowed without editor_id.
• All relevant tests pass with the required code coverage.

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This PR ensures consistent locking behavior across all relevant operations in line with the documentation and expected usage.

[PrakharJain1509]

Hey, @FlorianJacta and @bobbyshermi
I have created this PR addressing all the changes asked, Please review it and let me know if any changes are required.

[bobbyshermi]

What if the previous data of the data node has no append method.
In other words, what if in_memory_storage[self.id] has no append method?

[PrakharJain1509]

Ok I added a if instance condition to resolve that. Please review it and let me know if any changes required.