Check for nil UserName for Virtual MFA devices

[gdavison]

Checking for Virtual MFA Devices in an account where the root user has an MFA device causes a crash. This is because the root user has no "friendly" user name in the record returned by the AWS API.

Community Note

• Please vote on this pull request by adding a 👍 reaction to the original pull request comment to help the community and maintainers prioritize this request
• Please do not leave "+1" comments, they generate extra noise for pull request followers and do not help prioritize the request

Relates #11040

Release note for CHANGELOG:

NONE

No CHANGELOG entry because this is an unreleased bug, introduced in #11040

Output from acceptance testing:

$ make testacc TESTARGS='-run=TestAcc\(AWSUser_ForceDestroy_\|AWSIAMPolicyAttachment_Users_RenamedUser\|AWSUserLoginProfile_\|AWSUserGroupMembership_basic\)'

--- PASS: TestAccAWSUserLoginProfile_keybaseDoesntExist (21.78s)
--- PASS: TestAccAWSUser_ForceDestroy_AccessKey (24.89s)
--- PASS: TestAccAWSUser_ForceDestroy_LoginProfile (26.31s)
--- PASS: TestAccAWSUser_ForceDestroy_MFADevice (26.52s)
--- PASS: TestAccAWSUser_ForceDestroy_SSHKey (27.08s)
--- PASS: TestAccAWSUserLoginProfile_PasswordLength (27.38s)
--- PASS: TestAccAWSUserLoginProfile_notAKey (28.31s)
--- PASS: TestAccAWSUserLoginProfile_keybase (30.40s)
--- PASS: TestAccAWSUserLoginProfile_basic (37.46s)
--- PASS: TestAccAWSIAMPolicyAttachment_Users_RenamedUser (50.23s)
--- PASS: TestAccAWSUserGroupMembership_basic (108.67s)

[aeschright]

No nil!

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!