Optimize find delegation validators

[brentstone]

Describe your changes

Closes #3015.

Indicate on which release or other PRs this topic is based on

v0.33.0

Checklist before merging to draft

• [x] I have added a changelog
• [x] Git history is in acceptable state

[brentstone]

looks good besides the tiny comments

thanks, think I still may include the pruning of DelegationEpochs data. Realized I left a couple ToDos

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 85.81315% with 41 lines in your changes are missing coverage. Please review.

Project coverage is 59.49%. Comparing base (97ec5b4) to head (4336b33). Report is 4 commits behind head on main.

Files	Patch %	Lines
crates/proof_of_stake/src/queries.rs	84.84%	10 Missing :warning:
crates/sdk/src/rpc.rs	0.00%	9 Missing :warning:
crates/light_sdk/src/reading/asynchronous/pos.rs	0.00%	5 Missing :warning:
crates/namada/src/ledger/governance/mod.rs	87.09%	4 Missing :warning:
crates/sdk/src/queries/vp/pos.rs	0.00%	4 Missing :warning:
crates/proof_of_stake/src/lib.rs	97.79%	3 Missing :warning:
crates/sdk/src/signing.rs	0.00%	2 Missing :warning:
crates/sdk/src/tx.rs	0.00%	2 Missing :warning:
crates/governance/src/storage/mod.rs	50.00%	1 Missing :warning:
crates/light_sdk/src/transaction/governance.rs	0.00%	1 Missing :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3043      +/-   ##
==========================================
+ Coverage   59.39%   59.49%   +0.09%     
==========================================
  Files         298      298              
  Lines       92771    92967     +196     
==========================================
+ Hits        55104    55310     +206     
+ Misses      37667    37657      -10     

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