fix state_dict() hanging process with torchmetrics 0.4

[awaelchli]

What does this PR do?

Fixes hanging process due to state_dict() not being called on all ranks.
This is necessary after torchmetrics 0.4, PR Lightning-AI/torchmetrics#302
PL master is fine.
This fix will be included in the weekly patch release #8198

Additional context: Lightning-AI/torchmetrics#331

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[codecov]

Codecov Report

Merging #8218 (2b05aed) into release/1.3.x (0ba147d) will decrease coverage by 6%.
The diff coverage is 0%.

@@              Coverage Diff               @@
##           release/1.3.x   #8218    +/-   ##
==============================================
- Coverage             92%     86%    -6%     
==============================================
  Files                200     200            
  Lines              13067   13069     +2     
==============================================
- Hits               11987   11183   -804     
- Misses              1080    1886   +806     

[awaelchli]

@Borda I think we need to combine our two PRs #8206
Mine fixes the hanging process, yours fixes the api compatibility. How do we want to proceed?

[Borda]

Mine fixes the hanging process, your's fixes the api compatibility. How do we want to proceed?

I think we shall merge both kinds of independently (do not matter on order) anyway we need Admin to do this merge... :]

[kaushikb11]

@Borda Admins are in a different timezone!

[awaelchli]

We asked admin to merge this one with failing tests, then #8206 will follow to fix it.

[tchaton]

LGTM !