SDK+client/PoS: allow to set a receiver target for claim reward tx

[tzemanovic]

Describe your changes

Follow-up to #4402 (based on it - diff https://github.com/anoma/namada/pull/4427/files/9b01f9a79e7c34a17102d7bafc7c040ce3ccab83..54d1162d28f5e7f007e8a5f4386f8f6e3259e635).

This allow to optionally set the rewards target in the SDK and the client and it should only be used once the updated tx is deployed on-chain.

Checklist before merging

• If this PR has some consensus breaking changes, I added the corresponding breaking:: labels
  • This will require 2 reviewers to approve the changes
• If this PR requires changes to the docs or specs, a corresponding PR is opened in the namada-docs repo
  • Relevant PR if applies:
• If this PR affects services such as namada-indexer or namada-masp-indexer, a corresponding PR is opened in that repo
  • Relevant PR if applies:

[codecov]

Codecov Report

Attention: Patch coverage is 51.66667% with 29 lines in your changes missing coverage. Please review.

Project coverage is 74.46%. Comparing base (c29fd32) to head (54d1162).
Report is 33 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/sdk/src/tx.rs	36.36%	14 Missing ⚠️
wasm/tx_claim_rewards/src/lib.rs	0.00%	11 Missing ⚠️
crates/tx_prelude/src/proof_of_stake.rs	0.00%	2 Missing ⚠️
crates/proof_of_stake/src/lib.rs	92.30%	1 Missing ⚠️
crates/sdk/src/lib.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4427      +/-   ##
==========================================
- Coverage   74.54%   74.46%   -0.08%     
==========================================
  Files         339      339              
  Lines      110504   110658     +154     
==========================================
+ Hits        82374    82406      +32     
- Misses      28130    28252     +122     

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