Fix bug in MeanAveragePrecision.coco_to_tm

[SkafteNicki]

What does this PR do?

Fixes #2587

Before submitting

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

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📚 Documentation preview 📚: https://torchmetrics--2588.org.readthedocs.build/en/2588/

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 36%. Comparing base (1b77689) to head (d284694).
Report is 96 commits behind head on master.

❗ There is a different number of reports uploaded between BASE (1b77689) and HEAD (d284694). Click for more details.

HEAD has 80 uploads less than BASE

Flag	BASE (1b77689)	HEAD (d284694)
Windows	6	3
python3.8	6	3
cpu	40	20
torch1.13.1+cpu	6	3
torch1.11.0+cpu	2	1
Linux	24	12
python3.9	16	8
torch1.12.1+cpu	2	1
torch1.10.2+cpu	2	1
torch2.0.1+cpu	6	3
python3.10	10	5
torch2.3.0+cpu	6	3
python3.11	8	4
macOS	10	5
torch2.0.1	4	2
torch1.13.1	2	1
torch2.2.2+cpu	4	2
torch2.1.2+cpu	2	1
torch2.3.0	2	1
torch2.2.2	2	1

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #2588     +/-   ##
========================================
- Coverage      69%     36%    -33%     
========================================
  Files         314     314             
  Lines       17696   17700      +4     
========================================
- Hits        12198    6347   -5851     
- Misses       5498   11353   +5855