Fix accumulated_grad_batches typehint

[ananthsub]

Found this when going through the trainer constructor and various connectors.

The typhint was inconsistent with the trainer behavior. List[list] is not supported and raised a TypeError if passed in. This PR removes the misleading typehint from the trainer constructor

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Fixes #<issue_number>

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[codecov]

Codecov Report

Merging #9071 (3b0fab2) into master (538e743) will decrease coverage by 4%.
The diff coverage is 100%.

❗ Current head 3b0fab2 differs from pull request most recent head 1937493. Consider uploading reports for the commit 1937493 to get more accurate results

@@           Coverage Diff           @@
##           master   #9071    +/-   ##
=======================================
- Coverage      92%     88%    -4%     
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  Files         178     178            
  Lines       14659   14694    +35     
=======================================
- Hits        13495   12917   -578     
- Misses       1164    1777   +613