Mint limit is not reduced when the Vault is burning TAU
Upon burning TAU, it incorrectly updates the `currentMinted` when Vault is acting on behalf of users.\\nWhen the burn of `TAU` is performed, it calls `_decreaseCurrentMinted` to reduce the limit of tokens minted by the Vault:\\n```\\n    function _decreaseCurrentMinted(address account, uint256 amount) internal virtual {\\n        // If the burner is a vault, subtract burnt TAU from its currentMinted.\\n        // This has a few highly unimportant edge cases which can generally be rectified by increasing the relevant vault's mintLimit.\\n        uint256 accountMinted = currentMinted[account];\\n        if (accountMinted >= amount) {\\n            currentMinted[msg.sender] = accountMinted - amount;\\n        }\\n    }\\n```\\n\\nThe issue is that it subtracts `accountMinted` (which is currentMinted[account]) from `currentMinted[msg.sender]`. When the vault is burning tokens on behalf of the user, the `account` != `msg.sender` meaning the `currentMinted[account]` is 0, and thus the `currentMinted` of Vault will be reduced by 0 making it pretty useless.\\nAnother issue is that users can transfer their `TAU` between accounts, and then `amount > accountMinted` will not be triggered.
A simple solution would be to:\\n```\\n     uint256 accountMinted = currentMinted[msg.sender];\\n```\\n\\nBut I suggest revisiting and rethinking this function altogether.
`currentMinted` is incorrectly decreased upon burning so vaults do not get more space to mint new tokens.
```\\n    function _decreaseCurrentMinted(address account, uint256 amount) internal virtual {\\n        // If the burner is a vault, subtract burnt TAU from its currentMinted.\\n        // This has a few highly unimportant edge cases which can generally be rectified by increasing the relevant vault's mintLimit.\\n        uint256 accountMinted = currentMinted[account];\\n        if (accountMinted >= amount) {\\n            currentMinted[msg.sender] = accountMinted - amount;\\n        }\\n    }\\n```\\n