cast to int64_t in GetAsInt32()

https://github.com/4paradigm/OpenMLDB/blob/0c2592da4da94d34804560ada03dd743aa7f25b5/hybridse/include/node/sql_node.h#L975-L991

Look at hybridse/include/node/sql_node.h lines 975-991, specifically the GetAsInt32() method. The issue suggests adding a cast to int64_t. Check the surrounding code to understand the data types involved and ensure the cast is safe. Run any existing tests related to SQL node parsing or integer conversions to verify the change.

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