Deprecate DistributedType in favor of StrategyType

[kaushikb11]

What does this PR do?

Part of #9932

Kudos to @ethanwharris for sharing the Enum deprecation trick! 🥳

Does your PR introduce any breaking changes? If yes, please list them.

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[ethanwharris]

Awesome, LGTM 😃

[rohitgr7]

there are still some instances of it left inside dqn example inside notebooks..

[four4fish]

Great! Thank you for fixing this.
One big step towards #10422

[tchaton]

LGTM !

i'm dumb

[codecov]

Codecov Report

Merging #10505 (8a29ecb) into master (fa0ed17) will increase coverage by 0%.
The diff coverage is 90%.

@@           Coverage Diff           @@
##           master   #10505   +/-   ##
=======================================
  Coverage      92%      92%           
=======================================
  Files         179      178    -1     
  Lines       16288    16226   -62     
=======================================
- Hits        15060    15009   -51     
+ Misses       1228     1217   -11