fix: Content is reset while editing credential with kubeconfig

Created by: harrisonliu5

Signed-off-by: harrisonliu5 harrisonliu_5@163.com

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind bug

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes ##1907 (closed)

Special notes for reviewers:

Additional documentation, usage docs, etc.:

/assign @johnniang