Fix GCS Auth Issues

[joe-elliott]

What this PR does:
Fixes an issue brought to us by several members of the community. On startup the following error was thrown:

 caller=main.go:92 msg="error running Tempo" err="failed to init module services error initialising module: store: failed to create store getting bucket attrs: Get \"https://storage.googleapis.com/storage/v1/b/<Bucket name is here but removed it >?alt=json&prettyPrint=false&projection=full\": oauth2: cannot fetch token: 400 Bad Request\nResponse: {\"error\":\"invalid_scope\",\"error_description\":\"Invalid OAuth scope or ID token audience provided.\"}"

Upon inspection we we were creating our client differently than Cortex/Loki. This change fixes the issue as confirmed by @Whyeasy. Thank you for all the help.

Which issue(s) this PR fixes:
Fixes #

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]