Lazy-mode schema does not reflect timezone conversion

[erinov1]

Polars version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of Polars.

Issue description

In eager mode, the schema is aware of timezone conversions:

df = pl.DataFrame({"dt": [datetime.datetime(2021, 1, 1)]})
df.with_columns(
    pl.col("dt").dt.replace_time_zone("UTC").dt.convert_time_zone("America/New_York")
).schema

{'dt': Datetime(tu='us', tz='America/New_York')}

But in lazy mode the schema does not reflect the timezone conversion:

ldf = df.lazy()
ldf.with_columns(
    pl.col("dt").dt.replace_time_zone("UTC").dt.convert_time_zone("America/New_York")
).schema

{'dt': Datetime(tu='us', tz='UTC')}

Reproducible example

import datetime
import polars as pl

ldf = pl.DataFrame({"dt": [datetime.datetime(2021, 1, 1)]}).lazy()
ldf.with_columns(
    pl.col("dt").dt.replace_time_zone("UTC").dt.convert_time_zone("America/New_York")
).schema

Expected behavior

The schema in lazy mode should also be

{'dt': Datetime(tu='us', tz='America/New_York')}

Installed versions

---Version info---
Polars: 0.16.6
Index type: UInt32
Platform: macOS-13.2-arm64-arm-64bit
Python: 3.10.9 (main, Feb 12 2023, 18:51:31) [Clang 14.0.0 (clang-1400.0.29.202)]
---Optional dependencies---
pyarrow: 11.0.0
pandas: 1.5.3
numpy: 1.24.2
fsspec: 2023.1.0
connectorx: <not installed>
xlsx2csv: <not installed>
deltalake: <not installed>
matplotlib: 3.7.0

[MarcoGorelli]

thanks for reporting 🙏 working on a PR