[feature]: allow configuring mock price oracle with per asset rates

[ffranr]

Description:

Currently, the inbuilt mock price oracle allows configuration by setting a single rate for all assets. This feature request proposes enhancing the mock price oracle configuration to support setting separate rates for different asset IDs or asset group keys.

Benefits:

• More granular control over mock price oracle settings in test environments.
• Enhanced flexibility for scenarios where assets require distinct price configurations.