[megatron] fix: retain MLA config in mcore config converter

[Yangruipis]

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• in the current check_and_disable_incompatible_configs function, we will drop config if it's not an attribute of TransformerConfig, however when using MLATransformerConfig, this funcion will drop mla config like q_lora_rank, and cause a lots of problems in the downstream pipeline
• this pr refactored check_and_disable_incompatible_configs to a factory function check_and_construct_configs , which accecpt a class type bounded with TransformerConfig, and return a TransformerConfig instance.

@ETOgaosion

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[gemini-code-assist]

Code Review

The code changes refactor the check_and_disable_incompatible_configs function to a factory function check_and_construct_configs, which accepts a class type bounded with TransformerConfig and returns a TransformerConfig instance. This addresses the issue of dropping subclass-specific configurations. The review includes suggestions to update the docstring for the new function and remove the print statement.