Is there an existing issue for this?

• I have searched the existing issues

Current behaviour

@theStack introduced support for supplying a tag_name to the MiniWallet constructor in #29939.

I was going to make a test use that feature, but uncovered the following issues.

For some tag_names (like "12"), sendrawtransaction indirectly calls VerifyTaprootCommitment() which ends up calling secp256k1_xonly_pubkey_tweak_add_check() which ends up failing on the last condition - doing the parity check.

There's also an issue earlier during initialization on the Python side where tag_names like "12345" cause tweak_add_pubkey to return None, which leads to an exception.

Expected behaviour

Should support any tag_name value or document which ones are allowed.

Steps to reproduce

I've modified test/functional/feature_framework_miniwallet.py to expose issues I've encountered in 0ec889c.

Relevant log output

No response

How did you obtain Bitcoin Core

Compiled from source

What version of Bitcoin Core are you using?

master@5d280130446d57d653c749005a2e363265d87686

Operating system and version

NixOS (Linux)

Machine specifications

No response