[Feature] support `CAST` in alias function

[qidaye]

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Description

We have introduced alias function in #6261.
Current we only support FunctionCallExpr in alias function, support for cast is required in some cases.

Use case

In the case of some database access, there are some special functions that are not supported and can be implemented by cast.

eg:

-- ALL : for any type 
CREATE ALIAS FUNCTION decimal(ALL, INT, INT) WITH PARAMETER(col, precision, scale) 
    AS CAST(col AS decimal(precision, scale));

CREATE ALIAS FUNCTION varchar(all, int) WITH PARAMETER(text, length) 
        AS cast(text as varchar(length));

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