Improve Test_InsertOrEjectMedia, address gosec issues

[Didainius]

This PR improves Test_InsertOrEjectMedia which sometimes fails. The reason is - in rare cases VCD lags to update VM structure after media is ejected. The hardware item still persists. In my experimentation, this could happen once in 6-8hours when the test is run in a loop.

Additionally:

• Addresses new gosec reported issues
• Bumps GitHub actions to use Go 1.21 by default