Price-feeder: clean up error messages

[adamewozniak]

Summary

We should clean up any copied error messages in our price feeder to use price-feeder/oracle/types/errors.go.

Ref: #1339 (comment)

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For Admin Use

• Not duplicate issue
• Appropriate labels applied
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[robert-zaremba]

Since price feeder noise is going back and forth, let's already assign it and move this task forward. @adamewozniak feel free to reassign and add it to Linear.