fix: Add empty message in image builder create modal

Created by: harrisonliu5

Signed-off-by: harrisonliu5 harrisonliu@kubesphere.io

What type of PR is this?

/kind bug

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

Special notes for reviewers:

Does this PR introduced a user-facing change?

fix: Add empty message in image builder create modal

Additional documentation, usage docs, etc.: