fix: handle deserialization of TaskResult

[mikeshultz]

What I did

Handles deserialization of TaskResult.

fixes: #107

How I did it

ScalarDatapoint may be in dict form.

How to verify it

>>> from silverback.types import Datapoints
>>> from taskiq import TaskiqResult
>>> from silverback.recorder import TaskResult
>>> from silverback_cluster_common.types import InstancedTaskResult
>>> result = TaskResult.from_taskiq(TaskiqResult(is_err=False, log=None, return_value={'foo': 123, 'value': 0.01}, execution_time=0.39, labels={}, error=None))
>>> TaskResult.model_validate(result.model_dump())
TaskResult(task_name='handle_transfer', execution_time=0.39, error=None, completed=datetime.datetime(2024, 8, 9, 3, 26, 39, 738962, tzinfo=TzInfo(UTC)), block_number=6464337, metrics=Datapoints(root={'foo': ScalarDatapoint(type='scalar', data=123), 'value': ScalarDatapoint(type='scalar', data=0.01)}))
>>> 

Checklist

• Passes all linting checks (pre-commit and CI jobs)
• New test cases have been added and are passing
• Documentation has been updated
• PR title follows Conventional Commit standard (will be automatically included in the changelog)