Replace request number by package name in excluded requests

[saraycp]

In both webui and API, excluded requests list shows the package name, before there was only the request number.

Fixes: #8524

How to test?

osc api -X GET '/staging/<project>/excluded_requests'

or in webui

/staging_workflows/<staging_workflow_id>/excluded_requests

[coolo]

You're still required to enter a number to add excludes in the webui, but it's to be seen how often people actually use this. So far we relied purely on the command line for this, so displaying it properly is more important.

[saraycp]

You're still required to enter a number to add excludes in the webui, but it's to be seen how often people actually use this. So far we relied purely on the command line for this, so displaying it properly is more important.

@coolo, I opened this issue so we don't forget it: #8677