hey there! is it possible to halt trading on UniSwap? in case there's a problem with the token's contract, to be able to migrate to a fixed one

No you can't as far as I know

On v2 atleast

Because if a transaction was sent to uniswap pair through uniswap router if the uniswap was stopped trading then the amount the he put in was lost forever

So it can't be stopped

makes sense

On swaps I mean

maybe draining the liquidity would be the best solution

Yes but that can't stop all trading

Uniswap has no owner