Docs: Remove undocumented zero_division reference from dice_score docstring.

[rittik9]

What does this PR do?

Fixes #3258

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--3279.org.readthedocs.build/en/3279/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 32%. Comparing base (122a852) to head (451bd60).

❗ There is a different number of reports uploaded between BASE (122a852) and HEAD (451bd60). Click for more details.

HEAD has 4 uploads less than BASE

Flag	BASE (122a852)	HEAD (451bd60)
gpu	2	0
unittest	2	0

Additional details and impacted files

@@            Coverage Diff            @@
##           master   #3279      +/-   ##
=========================================
- Coverage      99%     32%     -67%     
=========================================
  Files          15     349     +334     
  Lines         195   19901   +19706     
=========================================
+ Hits          194    6376    +6182     
- Misses          1   13525   +13524     

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