fix: Incorrect logic in assert_series_equal for infinities

[lukemanley]

fixes #16859

main branch does not raise for the following example:

import polars as pl
from polars.testing import assert_series_equal

s1 = pl.Series([1.0])
s2 = pl.Series([float("inf")])

assert_series_equal(s1, s2)

This PR:

AssertionError: Series are different (value mismatch)
[left]:  [1.0]
[right]: [inf]

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.74%. Comparing base (725c960) to head (2ab8da4).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #20763      +/-   ##
==========================================
- Coverage   79.74%   79.74%   -0.01%     
==========================================
  Files        1561     1561              
  Lines      222012   222012              
  Branches     2530     2530              
==========================================
- Hits       177049   177040       -9     
- Misses      44381    44390       +9     
  Partials      582      582              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.