Fix failed batch operations printing result and passing silently

[BigRoy]

Bug

When a batch of operations fails (send_batch_operations, send_background_batch_operations(wait=True), OperationsSession.commit()):

1. The whole result is printed to stdout — noise in host application consoles and pipelines, not controllable by logging.
2. If the server reports success: false but no individual operation as failed, the method returns without raising, so the failure is silently ignored.
3. Missing operations key or an operation id not found in the sent operations raise KeyError / StopIteration instead of FailedOperations.

Fix

• Replace print with a warning log.
• Raise FailedOperations with the server response when no failed operation can be identified.
• Use .get("operations") and fall back to the operation result when the sent operation is not found.

Reproduce

Updating a non-existing folder (does not change any data):

import ayon_api
con = ayon_api.get_server_api_connection()
con.send_batch_operations("<project>", [{
    "type": "update",
    "entityType": "folder",
    "entityId": "0" * 32,
    "data": {"label": "x"},
}])
# develop: the result dict is printed to stdout, then FailedOperations is raised
# this PR: result is logged as a warning, FailedOperations is raised

Testing notes

• Snippet above, check the output goes through logging (e.g. silence it with logging.getLogger(con.log.name).setLevel(logging.ERROR)).
• tests/test_operations_result.py covers the silent failure case.

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