Prometheus datasource added in Grafana responding with 401

Hello. I am trying to add Prometheus Datasource in grafana through a config map in Kubernetes. Grafana UI keeps prompting to enter the username and password whenever the data source is selected, even after specifying their values as below. And also its converting few strings of the password to a Unicode format (eg password: xyz{s&a is replaced with password:xyz{s\u0026a}.
Can someone help with this?
- name: sauron-prometheus-new
type: prometheus
access: browser
org_id: 1
isDefault: false
version: 2
editable: true
withCredentials: true
user: abc
password: xyz{s&a