gRPC endpoint ConvertGasToZeta is unsafe which allow to panic this endpoint very easely by providing a gas price that cant be converted in Integer. Fortunatelly, there is a recovery, so the program doesnt crash, which is why this is only submitted as a Low, otherwise that would be probably a High as you could DoS zetacored at will. 
This is confirmed throught directly reaching the public endpoint as follows:
While a more normal error would be as follows (for unknow chain):
I also added this unit test, which also confirm the issue and the a panic is occuring internally but recovered, as the error message match the panic.
Even if this error is recovered, I would recommend the team to introduce a validation ConvertGasToZeta function such that the program return proper error, and not a panicked error, which doesnt give proper information about the error.
https://github.com/code-423n4/2023-11-zetachain/blob/main/repos/node/x/crosschain/keeper/zeta_conversion_rate.go#L27
