CVE Allowlist should not allow empty cve.

[bupd]

If you are reporting a problem, please make sure the following information are provided:

Expected behavior

The cve allowlist should not allow empty names.

Actual Behaviour

The CVE Allowlist allows empty cve to be present.

Steps to reproduce the problem:

1. Navigate to configuration > security > cve allowlist > add
2. then type any CVE or characters ksljd then press Enter.
3. then click on ADD. see empty line as CVE.

Versions:

• harbor version: [2.12.0]
• docker engine version: [y.y.y]
• docker-compose version: [z.z.z]

Additional context:

• Harbor config files: You can get them by packaging harbor.yml and files in the same directory, including subdirectory.
• Log files: You can get them by package the /var/log/harbor/ .

[AllForNothing]

There used to be a validator for the CVE names, but it was removed because we could not find a suitable rule.
Most CVEs are named with CVE-XXX-XXX, but there are always exceptions. So we decided to remove the validator.
And now you can add any CVEs, even CVEs with all spaces.

[bupd]

CVEs with all spaces

I believe we should not allow this one. seems outrageous to me.

[stonezdj]

Maybe we should check it should be non-empty.