Custom function cannot be accessed across database

[李斌松]

Custom function cannot be accessed across database,
example: The registration function json_extract_value is in database A, and
A.json_extract_value cannot be called in the database B

SessionCatalog.java

externalCatalog.getFunction(currentDb, name.funcName)

to

externalCatalog.getFunction(name.database.getOrElse(currentDb), name.funcName)