Fix: add customAttributes to edit account request

[schultek]

The customAttributes field is not encoded in the final request object, therefore when calling setCustomUserClaims the claims are never updated.

[spoeck]

I have tested this PR, works as expected -> should be merged

[sgehrman]

Just spent hours trying to figure out why this isn't working.

Any reason why this hasn't been merged yet?

[Cobolt77]

Please merge with master :)

[sgehrman]

What is going on?

[livtanong]

I think maybe this hasn't been merged because there's a lot of other changes in this PR. And there's this entire other method added as well: https://github.com/appsup-dart/firebase_admin/pull/13/files#diff-0b1edb4d91ddbe43e7a03462af85a8b215c06e6a3b988f8fd2a17f7b7e27690aR38

So perhaps to aid in this being merged in, this PR could be split up into three parts:

1. The actual fix for customAttributes (Seems like this is just one line)
2. The new method as a proposal
3. All other style and minor refactorings

[schultek]

I think this just isn't maintained anymore. There was no activity by the owner for a long time on any issue or pr.

I have forked this for my own use a while ago, you can use this if you want, but I'm not actively working on it: https://github.com/schultek/firebase_admin

[sgehrman]

Two years later and still broken.