to_datetime may give incorrect results

[MarcoGorelli]

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

There are a few more cases of when NaiveDateTime.parse_from_string fails, but then the fallback NaiveDate.parse_from_string passes and "chops off" some data

Reproducible example

In [7]: pl.Series(['2020-January-01 12:34']).str.to_datetime('%Y-%B-%d %M:%S')
Out[7]:
shape: (1,)
Series: '' [datetime[μs]]
[
        2020-01-01 00:00:00
]

In [8]: datetime.strptime('2020-January-01 12:34', '%Y-%B-%d %M:%S')
Out[8]: datetime.datetime(2020, 1, 1, 0, 12, 34)

In [19]: pl.Series(['2020-January-01 10:43']).str.to_datetime('%Y-%B-%d %I:%M')
Out[19]:
shape: (1,)
Series: '' [datetime[μs]]
[
        2020-01-01 00:00:00
]

In [20]: datetime.strptime('2020-January-01 10:43', '%Y-%B-%d %I:%M')
Out[20]: datetime.datetime(2020, 1, 1, 10, 43)

Expected behavior

to either raise, or match datetime.strptime

Installed versions

--------Version info---------
Polars:      0.18.4
Index type:  UInt32
Platform:    Linux-5.10.102.1-microsoft-standard-WSL2-x86_64-with-glibc2.35
Python:      3.10.6 (main, Mar 10 2023, 10:55:28) [GCC 11.3.0]

----Optional dependencies----
numpy:       1.24.3
pandas:      2.0.2
pyarrow:     <not installed>
connectorx:  <not installed>
deltalake:   <not installed>
fsspec:      <not installed>
matplotlib:  3.7.1
xlsx2csv:    <not installed>
xlsxwriter:  <not installed>