Fix: Username length in projects users to match users

[oanasc]

Description of your changes

1. "Fixes #903": SSO user default project not getting set because the username vela_user.name doesn't have the same length as the username FK in vela_project_user This means users logging in have no permissions whatsoever unless someone manually adds it.

2. The e2e tests were failing due to k3s version 1.21 not being available. I've removed the version from the matrix

I have:

• [x] Read and followed KubeVela's contribution process.
• [x] Related Docs updated properly. In a new feature or configuration option, an update to the documentation is necessary.
• [ ] Run yarn lint to ensure the frontend changes are ready for review.
• [x] Run make reviewableto ensure the server changes are ready for review.
• [ ] Added backport release-x.y labels to auto-backport this PR if necessary.

Special notes for your reviewer

[oanasc]

The e2e tests checks for 1.21 are might need to be removed by a maintainer. Don't know if the matrix should include later versions of Kubernetes, i've just removed 1.21 because is not on the list of versions available for k3s anymore.

[oanasc]

Thank you both @FogDong and @anoop2811. Would need some help with these statuses especially 1.21 to be removed