[SPARK-46543][PYTHON][CONNECT] Make json_tuple throw PySparkValueError for empty fields

[zhengruifeng]

What changes were proposed in this pull request?

Make json_tuple throw PySparkValueError for empty fields

Why are the changes needed?

Python side should have the same check as the Scala side:

spark/sql/core/src/main/scala/org/apache/spark/sql/functions.scala

Lines 6330 to 6334 in fa4096e

	@scala.annotation.varargs
	def json_tuple(json: Column, fields: String*): Column = {
	require(fields.nonEmpty, "at least 1 field name should be given.")
	Column.fn("json_tuple", json +: fields.map(lit): _*)
	}

Does this PR introduce any user-facing change?

yes

How was this patch tested?

added ut

Was this patch authored or co-authored using generative AI tooling?

no

[zhengruifeng]

cc @HyukjinKwon and @itholic

[zhengruifeng]

thanks, merged to master