[release pipeline] Allow retry of 'Public Release' stage

[mthalman]

An attempt to retry the Public Release stage of the SB release pipeline had failed due to an attempt to publish a pipeline artifact with the same name as the original attempt. Duplicate artifact names are not allowed. This resulted in the following error: Artifact Signatures already exists for build 2708303.

We should enable this to work by appending a job attempt number to the artifact name.

Example failed build (internal link)

[ellahathaway]

PR: https://dev.azure.com/dnceng/internal/_git/dotnet-release/pullrequest/52064