BUG: Timedelta does not accept ISO 8601 duration strings with 3 digit hours or minutes

[rosstitmarsh]

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Reproducible Example

import pandas as pd
pd.Timedelta('PT100H')

Issue Description

An ISO 8601 duration string raises a ValueError when the hours or minutes part is longer than 2 digits.

There is an explicit check for the length of the hours and minute parts in the parser

pandas/pandas/_libs/tslibs/timedeltas.pyx

Line 883 in f9be5d9

if c in ["H", "M"] and len(number) > 2:

A duration of 100 hours is obviously valid, pd.Timedelta(100, unit='hours') works like expected.

Expected Behavior

import pandas as pd
assert pd.Timedelta('PT100H') == pd.Timedelta(100, unit='hours')
assert pd.Timedelta('PT100M') == pd.Timedelta(100, unit='minutes')

Installed Versions

INSTALLED VERSIONS

commit : 2e218d1
python : 3.11.1.final.0
python-bits : 64

pandas : 1.5.3
numpy : 1.24.2
pytz : 2022.7.1
dateutil : 2.8.2
setuptools : 65.5.0
pip : 22.3.1
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : None
IPython : None
pandas_datareader: None
bs4 : None
bottleneck : None
brotli : None
fastparquet : None
fsspec : None
gcsfs : None
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : None
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : None
snappy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
zstandard : None
tzdata : None

[jbrockmendel]

PR would be welcome.

What is "PT" in this context?

[rosstitmarsh]

P prefixes all ISO 8601 durations
T separates the years/months/day parts from the hour/minute/second parts. As P1M is one month but PT1M is 1 minute.

[rosstitmarsh]

Closing in favour of #51882