Incorrect units on Namespace price API

**Describe the bug**
The response returned by the API dictates that units=STX, however the actual amount returned is in Micro Stacks.
**To Reproduce**
Steps to reproduce the behavior:
1. Hit the API: https://api.mainnet.hiro.so/v2/prices/namespaces/something
2. Check response

**Expected behavior**
I think the response should return 'uSTX' as the unit and the documentation should be updated to reflect this.

**Screenshots**

**Additional context**
Link to documentation: https://hirosystems.github.io/stacks-blockchain-api/#tag/Names/operation/get_namespace_price