Adjust priority of quota project sources

[michalskalski]

'GOOGLE_CLOUD_QUOTA_PROJECT' env variable should override quota project setting from credentials file. This is a behavior of previous auth code: https://github.com/googleapis/google-api-go-client/blob/main/internal/creds.go#L242-L261

It is trying to solve issue described in #10804

To activate it would required additional change in https://github.com/googleapis/google-api-go-client: googleapis/google-api-go-client#2767

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[codyoss]

Please see comments on the associated issue. I would like something like these changes in the library. There is just some other associated changes that would need to happen at the same time. If you would like to work on this I am happy to explain more in the new issue I created for this request, but if not that is fine to and we will get to it in the not too distant future. Thanks again.

[michalskalski]

@codyoss if you have some general idea how you would like to see this being solved in long term, please share it in the issue. I will try find time to implement. If you already know specifically how this should be implemented and it just matter of finding time, then I don't mind wait for your implementation. What is currently in repo already fixed my initial problem

[codyoss]

@michalskalski We will get to it 😄 Just wanted to make sure I was not stealing an oppertunity away if you wanted to make a contribution. Thanks again for the report and glad the PR fixed the issue for you.