[#7778] feat(client-python): Support statistics python client config for gravitino client

[TEOTEO520]

What changes were proposed in this pull request?

This PR implements the Python client for the Statistics API in Apache Gravitino. The implementation includes:

• Statistics API interfaces (Statistic, StatisticValue, StatisticValues, SupportsStatistics)
• DTOs for statistics data transfer (StatisticDTO, StatisticValueDTO)
• Request/Response classes (StatisticsUpdateRequest, StatisticListResponse)
• Client operations class (MetadataObjectStatisticsOperations)
• Exception handling (IllegalStatisticNameException, UnmodifiableStatisticException)

Why are the changes needed?

• List statistics for metadata objects (tables)
• Update statistics with custom values
• Drop statistics by name

Fix: #(issue)

Does this PR introduce any user-facing change?

Yes, this PR adds new user-facing APIs for Python users:

1. New API classes: SupportsStatistics interface for objects that support statistics operations
2. New methods: list_statistics(), update_statistics(), drop_statistics()
3. New factory class: StatisticValues for creating statistic values of different types

How was this patch tested?

• Added unit tests in tests/unittests/test_statistics_api.py covering all components