Support casting String to Time

[d-reynol]

Checks

• I have checked that this issue has not already been reported.
• I have confirmed this bug exists on the latest version of Polars.

Reproducible example

import datetime as dt
import polars as pl
# This works and produces the expected output
pl.Series([dt.date(2023, 12, 31)]).cast(pl.String).cast(pl.Date)
shape: (1,)
Series: '' [date]
[
	2023-12-31
]
# This errors
pl.Series([dt.time(12, 14, 9)]).cast(pl.String).cast(pl.Time)
polars.exceptions.InvalidOperationError: conversion from `str` to `time` failed in column '' for 1 out of 1 values: ["12:14:09"]

Log output

No response

Issue description

I can cast strings to dates, but not to times.

Using .str.to_time() works, but the current behavior should (ideally) be consistent

Expected behavior

Should be able to cast strings to times

Installed versions

--------Version info---------
Polars:               1.0.0
Index type:           UInt32
Platform:             Windows-10-10.0.19045-SP0
Python:               3.12.0 (tags/v3.12.0:0fb18b0, Oct  2 2023, 13:03:39) [MSC v.1935 64 bit (AMD64)]
----Optional dependencies----
adbc_driver_manager:  <not installed>
cloudpickle:          <not installed>
connectorx:           <not installed>
deltalake:            <not installed>
fastexcel:            <not installed>
fsspec:               <not installed>
gevent:               <not installed>
great_tables:         <not installed>
hvplot:               <not installed>
matplotlib:           <not installed>
nest_asyncio:         <not installed>
numpy:                1.26.4
openpyxl:             <not installed>
pandas:               2.2.2
pyarrow:              <not installed>
pydantic:             <not installed>
pyiceberg:            <not installed>
sqlalchemy:           <not installed>
torch:                <not installed>
xlsx2csv:             <not installed>
xlsxwriter:           <not installed>

[stinodego]

Agree we should support casting String to Time. This is not a bug though, it's simply not supported yet. I'll rebrand this as a feature request and accept it.

[d-reynol]

thank you!

[Biswas-N]

Can I take up this task?

[stinodego]

Can I take up this task?

Sure! Take a look at how casting is implemented for String to Date, that should give you a good starting point.

[ntn-nicholas]

Has there been any progress/findings on this issue? I'm interested in also contributing on this