## What changes were proposed in this pull request?
This pr adds `transform_values` function which applies the function to each entry of the map and transforms the values.
```javascript
> SELECT transform_values(map(array(1, 2, 3), array(1, 2, 3)), (k,v) -> v + 1);
map(1->2, 2->3, 3->4)
> SELECT transform_values(map(array(1, 2, 3), array(1, 2, 3)), (k,v) -> k + v);
map(1->2, 2->4, 3->6)
```
## How was this patch tested?
New Tests added to
`DataFrameFunctionsSuite`
`HigherOrderFunctionsSuite`
`SQLQueryTestSuite`
Closes#22045 from codeatri/SPARK-23940.
Authored-by: codeatri <nehapatil6@gmail.com>
Signed-off-by: Takuya UESHIN <ueshin@databricks.com>
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