Prop 34: Upgrade quicksilverd to v1.5.3

This proposal aims to upgrade Quicksilver mainnet to v1.5.3 of quicksilverd.

This non-functional upgrade ensures consistent usage of math.Int across interchainstaking and participation rewards modules instead of a mixture of uint64 and math.Int which could lead to overflows when converting large values between the two.

A changelog can be found here: https://github.com/quicksilver-zone/quicksilver/releases/tag/v1.5.3