rpc: allow multiple data outputs #35637

Context

Transaction creation RPCs currently reject more than one data output. This restriction prevents callers from creating transactions with multiple OP_RETURN outputs.

Changes

• Allow multiple data outputs in ParseOutputs().
• Preserve each data output's corresponding payload.
• Keep duplicate Bitcoin address rejection unchanged.
• Update the RPC help text.
• Add functional coverage for multiple data outputs in createrawtransaction and createpsbt.
• Update the bumpfee test to reflect the new behavior.

Testing

rpc_rawtransaction.py 
rpc_psbt.py           
wallet_bumpfee.py     

Both data outputs are verified against their expected scripts:

6a01aa
6a01bb

Fixes #32478

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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35637.

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Reviews

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dupe of https://github.com/bitcoin/bitcoin/pull/32790