CASE with NULL branch does not coerce when passed to aggregate function

[erratic-pattern]

Describe the bug

Type coercion doesn't seem to handle NULL in a CASE branch when used inside of an aggregate.

To Reproduce

In Datafusion CLI:

> CREATE TABLE example(data double precision);
0 row(s) fetched.
Elapsed 0.005 seconds.

> SELECT sum(CASE WHEN data is NULL THEN NULL ELSE data + 1 END) FROM example;
Error during planning: Execution error: User-defined coercion failed with Execution("Sum not supported for Null") No function matches the given name and argument types 'sum(Null)'. You might need to add explicit type casts.
        Candidate functions:
        sum(UserDefined)

Expected behavior

NULL type should coerce to the ELSE branch type.

Additional context

No response

[jayzhan211]

I think we should fix CASE expression to get something like int64(0) or float(0) based on the data type of data for null

This does not seem correct for all the case

datafusion/datafusion/expr/src/expr_schema.rs

Line 115 in fe66daa

Expr::Case(case) => case.when_then_expr[0].1.get_type(schema),

[Weijun-H]

take