refactor: Spark ascii signature away from user_defined

[kumarUjjawal]

Which issue does this PR close?

• Part of Avoid use of Signature::user_defined for normal functions #12725

Rationale for this change

As per the goal stated that we should avoid using the user_defined in useful places.

What changes are included in this PR?

• Refactored Spark ascii to not use user_defined.
• Checked the Spark code to make sure it follows the same convention

Are these changes tested?

• This is a refactoring so no new tests were added but all previous test pass.

Are there any user-facing changes?

[Jefffrey]

Thanks @kumarUjjawal