datetime_range PanicException with nanosecond interval

[cmdlineluser]

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 polars as pl

pl.datetime_range(pl.date(2022, 1, 1), pl.date(2022, 1, 1), interval="1ns", time_unit="ms", eager=True)
# PanicException: assertion failed: step != 0

Log output

thread '<unnamed>' panicked at /rustc/a0d98ff0e5b6e1f2c63fd26f68484792621b235c/library/core/src/iter/adapters/step_by.rs:35:9:
assertion failed: step != 0

Issue description

Not too sure if this code actually makes sense or not - it was just some random experimentation.

I'm guessing it doesn't - and an appropriate error should be raised instead.

Expected behavior

No panic.

Installed versions

--------Version info---------
Polars:               1.14.0
Index type:           UInt32
Platform:             macOS-13.6.1-arm64-arm-64bit
Python:               3.12.2 (main, Feb  6 2024, 20:19:44) [Clang 15.0.0 (clang-1500.1.0.2.5)]

----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:               2.2.1
pyarrow:              15.0.2
pydantic:             <not installed>
pyiceberg:            <not installed>
sqlalchemy:           <not installed>
torch:                <not installed>
xlsx2csv:             <not installed>
xlsxwriter:           <not installed>