fix sqrt(-1.0::float8) should error, not return NaN

[xiedeyantu]

Which issue does this PR close?

• Closes PostgreSQL compatibility: sqrt(-1.0::float8) should error, not return NaN #22260.

Rationale for this change

DataFusion previously returned NaN for sqrt on negative floating-point inputs, for example sqrt((-1.0)::float8). This differs from PostgreSQL semantics, which raise an error for square root of a negative number.

This change makes sqrt return an execution error for out-of-domain negative inputs so its behavior is closer to PostgreSQL and avoids silently producing NaN for invalid inputs.

What changes are included in this PR?

• Updated the unary math UDF helper to support an optional validator callback for runtime input validation.
• Switched sqrt to use a named validator helper instead of inline predicate and error-string arguments.
• Added runtime validation for sqrt so negative inputs now raise cannot take square root of a negative number.
• Updated sqllogictests for sqrt:
  • negative literal inputs now expect an error
  • negative column inputs now expect an error
  • positive column coverage was retained using in-domain inputs

Are these changes tested?

Yes.

The change is covered by existing SQL logic tests and targeted validation runs:

• cargo test -p datafusion-functions sqrt
• cargo test -p datafusion-sqllogictest --test sqllogictests scalar

Are there any user-facing changes?

Yes.

sqrt now raises an execution error for negative inputs instead of returning NaN. This changes user-visible query behavior to better align with PostgreSQL semantics.

[xiedeyantu]

@Dandandan Could you help me take a look?

[kosiew]

@xiedeyantu
Looks 👍 to me

[xiedeyantu]

@xiedeyantu Looks 👍 to me

Thanks!

[xiedeyantu]

@Dandandan CI appears to be malfunctioning.