Cannot mint new treasury tokens for treasury with zero decimals

[smilingkylan]

Describe the bug
When you create a treasury that uses zero decimals, the mint action does not work properly.

To Reproduce

• Create a new treasury with a supply that has zero decimals
• Register as a voter
• Attempt to mint some treasury tokens
• You will get an "assertion failure with message: attempt to add asset with different symbol"

Expected behavior
Expect the amount of tokens to be minted... works fine with treasuries that have decimals (eg 4 decimal places)

Screenshots

Additional context
n/a