Return ErrBadRequest message with more relevant message

[mabdh]

Describe the bug
The error 400 ErrBadRequest

shield/internal/api/v1beta1/errors.go

Line 14 in fc0e9e6

ErrBadRequest = errors.New("invalid syntax in body")

returns message "invalid syntax in body"

However it is not always the case for some API. The invalid syntax might be in query param. We need to update the name to be more relevant.