Add avatar uri to the AuthenticationSessionAccountInformation

[isidorn]

This allows #136889

This API proposal is about adding an avatar: Uri to the AuthenticationSessionAccountInformation.
Code pointer https://github.com/microsoft/vscode/blob/isidorn/account-avatar/src/vscode-dts/vscode.proposed.authenticationSessionAccountInformationAdditions.d.ts#L11

@jrieken I plan to bring this up to the API call in January. Do let me know If I should do something else.

fyi @TylerLeonhardt

[jrieken]

We usually use iconPath, e.g

vscode/src/vscode-dts/vscode.d.ts

Line 16505 in 59c4ac3

iconPath?: Uri;

[isidorn]

Thanks. I have applied your suggestion.
Though avatarPath might be more clear, since it is not actually an icon.

[jrieken]

@isidorn fyi cleared the milestone so that this doesn't show in the API query/sync every week

[rzhao271]

@jrieken Could we add a feature-request label and a Backlog milestone to this issue for housekeeping, or would it end up reappearing on the API query?