Filter query parameters are not accepted by API

[jrwbabylonlab]

When sending multiple values for the same query param such as state. Below is what FE is sending:
?state[]=active&state[]=unbonding

However, backend is expecting it to be: ?state=active&state=unbonding.

We shall fix from FE as the pattern used in backend is already consumed by partners in phase-1. it will otherwise be a breaking change if we change it.
Alternatively, you can make the backend to accept formats like ?state=active,unbonding while maintain the ability to accept ?state=active&state=unbonding
The comma style is the most common way of sending multi-valued query params

[jrwbabylonlab]

#514