Support `length` function with non-string input

### What is the problem the feature request solves?

Since the length function with binary input panics, I have fallbacked it in #2349 and am trying to add a spark compatible length function in Datafusion https://github.com/apache/datafusion/issues/17474. Once it is resolved we can support the length function with non-string input in Comet.

### Describe the potential solution

Depends on: https://github.com/apache/datafusion/issues/17474

### Additional context