chore: mask backend sensitive data

[Yangyang96]

What type of PR is this?

What this PR does / why we need it:

avoid displaying sensitive data to user

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Additional documentation e.g., design docs, usage docs, etc.:

[coveralls]

Pull Request Test Coverage Report for Build 12663795420

Details

• 31 of 72 (43.06%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 47.524%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/apis/api.kusion.io/v1/types.go	0	1	0.0%
pkg/server/handler/stack/handler.go	1	4	25.0%
pkg/server/handler/workspace/handler.go	2	8	25.0%
pkg/server/manager/backend/backend_manager.go	11	19	57.89%
pkg/domain/request/workspace_request.go	9	19	47.37%
pkg/server/manager/backend/util.go	8	21	38.1%

Totals
Change from base Build 12646796222:	0.02%
Covered Lines:	10958
Relevant Lines:	23058

---

💛 - Coveralls

[liu-hm19]

lgtm