chore: ensure 2 decimal places

[npty]

Description

AXE-3183

This PR ensures that the gas_execute_multiplier which returns from the getFees API has 2 decimal places at maximum before put into the calculation.

Example

Try calling estimateGasFee function given axelar and optimism are source chain and destination chain respectively.

Before

Execute Gas Multiplier 1.1550000000000002
Execute Gas Multiplier 1.32
axelarnet to optimism fee: 0.00000000000412665 ETH
optimism to axelarnet fee: 0.01002625182289159 ETH

After

Execute Gas Multiplier 1.16
Execute Gas Multiplier 1.32
axelarnet to optimism fee: 0.000000000004133053 ETH
optimism to axelarnet fee: 0.010016512870193104 ETH

[canhtrinh]

looks good, let's add a changelog item and then release