[Feature Request]: add mempool acceptance API for Taproot spend flows #6309
Description
A change in structure for Taproot based contract resolution would be to collaboratively swap a script execution path in favor of a joint or aggregated key.
When doing this the spenders might want to maximize assurances that the alternative script-path transaction would be accepted into the mempool before they co-sign
Bitcoin Core has a feature to provide for this called testmempoolaccept, this could be added as a passthrough API, although in the case of a different backend that did not support the API it could offer an unavailable signal.
This way an application could use the API as an additional safety check when available.