[SPARK-40953][CONNECT][PYTHON] Fix `DataFrame.head` to collect specified number of rows
[SPARK-40953][CONNECT][PYTHON] Fix `DataFrame.head` to collect specified number of rows

### What changes were proposed in this pull request?
`head` should return `self.limit(n).toPandas()` instead of `self.toPandas()`

### Why are the changes needed?
bugfix

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
existing tests

Closes #38424 from zhengruifeng/connect_head_fix.

Authored-by: Ruifeng Zheng <21ef94aec54fae1a36abbd011347596ae66d9959@apache.org>
Signed-off-by: Hyukjin Kwon <2680965ad5aae29275c8fb10150cb10f5554e78b@apache.org>

ueshin/apache-spark,apache/spark,vinodkc/spark,ueshin/apache-spark,dongjoon-hyun/spark,vinodkc/spark,ueshin/apache-spark,zzcclp/spark,HyukjinKwon/spark,HyukjinKwon/spark,srowen/spark,vinodkc/spark,ueshin/apache-spark,wangyum/spark,HyukjinKwon/spark,srowen/spark,mahak/spark,mahak/spark,zzcclp/spark,wangyum/spark,zzcclp/spark,mahak/spark,HyukjinKwon/spark,zzcclp/spark,hvanhovell/spark,apache/spark,vinodkc/spark,apache/spark,wangyum/spark,apache/spark,wangyum/spark,apache/spark,mahak/spark,hvanhovell/spark,wangyum/spark,srowen/spark,HyukjinKwon/spark,srowen/spark,HyukjinKwon/spark,vinodkc/spark,srowen/spark,HyukjinKwon/spark,mahak/spark,dongjoon-hyun/spark,wangyum/spark,hvanhovell/spark,mahak/spark,hvanhovell/spark,vinodkc/spark,apache/spark,ueshin/apache-spark,dongjoon-hyun/spark,dongjoon-hyun/spark,dongjoon-hyun/spark,vinodkc/spark,ueshin/apache-spark,apache/spark,hvanhovell/spark,zzcclp/spark,wangyum/spark,srowen/spark,ueshin/apache-spark,hvanhovell/spark,mahak/spark,zzcclp/spark,zzcclp/spark,dongjoon-hyun/spark,hvanhovell/spark,dongjoon-hyun/spark,srowen/spark