fix: Resourcelimit placeholder style and tip message overlap

Created by: weili520

What type of PR is this?

/kind bug

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes ##2288 (closed) #https://github.com/kubesphere/console/issues/2425 #https://github.com/kubesphere/console/issues/2302

Special notes for reviewers:

https://user-images.githubusercontent.com/33231138/137854954-02601d6f-a148-47d5-aefb-1f503f27853d.mov

Does this PR introduced a user-facing change?

NONE

Additional documentation, usage docs, etc.: