fix: pearson changes inputs

[Borda]

What does this PR do?

reported by a user, thank you for also providing the fix

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• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
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• Did you make sure to update the docs?
• Did you write any new necessary tests?

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📚 Documentation preview 📚: https://torchmetrics--2765.org.readthedocs.build/en/2765/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41%. Comparing base (31ce89e) to head (f96cdef).
Report is 1 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (31ce89e) and HEAD (f96cdef). Click for more details.

HEAD has 388 uploads less than BASE

Flag	BASE (31ce89e)	HEAD (f96cdef)
Windows	17	3
python3.8	18	3
cpu	117	20
torch1.13.1+cpu	18	3
torch2.4.0+cpu	6	1
python3.11	16	3
torch1.12.1+cpu	6	1
Linux	78	13
python3.9	54	9
torch1.11.0+cpu	6	1
torch1.10.2+cpu	6	1
macOS	22	4
python3.10	29	5
torch2.0.1	12	2
torch2.3.1+cpu	12	2
torch2.0.1+cpu	17	3
torch2.2.2+cpu	12	2
torch1.13.1	6	1
torch2.4.0+cu121	6	1
torch2.1.2+cpu	6	1
torch2.4.0	4	1

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #2765     +/-   ##
========================================
- Coverage      69%     41%    -28%     
========================================
  Files         329     329             
  Lines       18077   18079      +2     
========================================
- Hits        12499    7466   -5033     
- Misses       5578   10613   +5035     

[SkafteNicki]

The concordance metric depended on the in-place normalization of the variances so I just had to add that to the metric.