fix: update vesting message server to handle base accounts correctly (backport: #12190)

[mmsqe]

Description

Closes: #XXXX

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[tac0turtle]

seems @alexanderbez mentioned this being state breaking: #12190 (comment), is there any reason you think otherwise?

[alexanderbez]

Yes, I do not feel comfortable backporting this given we're modifying a message handler which is state-machine breaking. We're changing API calls here. Concerns I have:

• Gas costs could differ
• Underlying accounts can be different