wallet: Add address validation in `sendtoaddress` RPC #33068

Is there a specific reason not to validate the address in the sendtoaddress RPC? This PR adds that.

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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33068.

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🚧 At least one of the CI tasks failed. _{Task previous releases, depends DEBUG: https://github.com/bitcoin/bitcoin/runs/46770879558} _{LLM reason (✨ experimental): The CI failed due to a syntax error in spend.cpp caused by a missing semicolon before a closing brace.}

<details><summary>Hints</summary>

Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

• Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

• A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

• An intermittent issue.

Leave a comment here, if you need help tracking down a confusing failure.

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